Precursor polyelectrolyte complexes compositions

ABSTRACT

The invention relates to compositions and methods of treatment employing compositions comprising polyelectrolyte complexes. The compositions include a water-soluble first polyelectrolyte bearing a net cationic charge or capable of developing a net cationic charge and a water-soluble second polyelectrolyte bearing a net anionic charge or capable of developing a net anionic charge. The total polyelectrolyte concentration of the first solution is at least 110 millimolar. The composition is free of coacervates, precipitates, latex particles, synthetic block copolymers, silicone copolymers, cross-linked poly(acrylic) and cross-linked water-soluble polyelectrolyte. The composition may be a concentrate, to be diluted prior to use to treat a surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of copending U.S. patentapplication Ser. No. 15/285,428, filed on Oct. 4, 2016, which is acontinuation of U.S. patent application Ser. No. 15/074,979 filed onMar. 18, 2016, now U.S. Pat. No. 9,486,800, issued on Nov. 8, 2016,which is a continuation of U.S. patent application Ser. No. 13/772,674,filed on Feb. 21, 2013, and now U.S. Pat. No. 9,309,435, issued on Apr.12, 2016, which is a continuation-in-part of U.S. patent applicationSer. No. 12/749,288, filed Mar. 29, 2010. The disclosure of each of theabove applications is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to polyelectrolyte complexes (“PECs”),their precursor compositions, and methods of making and using suchcompositions.

2. Description of Related Art

Consumers desire cleaning products that deliver additional benefits,e.g., that stay cleaner longer, inhibit the growth of microbes, maintainappearance, etc., all without the additional effort of a separatetreatment step in addition to regular cleaning.

Modification of household surfaces, both hard and soft, can provide manybenefits. It is important that such modifications be reversible, andhence, do not involve the formation of permanent covalent bonds betweenthe materials employed in the treatment.

It is also desirable that the modification be achieved via thin layersnot apparent to the unaided eye in order to minimize effort needed toachieve modification and to minimize any undesirable aesthetic changesin the appearance of surfaces.

In healthcare, there is a continuing desire to reduce hospital acquiredinfections. Modification of surfaces achieved with a minimum of effortto reduce microbial contamination is a recognized area of interest.Related to this goal is the desire to reduce transmission of diseasesfrom surface-borne microbial pathogens present in public places,including buildings and vehicles.

As in healthcare, removing and controlling the growth of microbes suchas bacteria and fungi is important in many industrial processes.Controlling microbe growth and achieving microbe removal from surfacesaffects productivity, practicality, and profitability of the process.For example, bacterial fouling of heat exchanger surfaces, fouling ofweb formation and handling equipment in the production or recycling ofpaper, and similar fouling in the processing of biomass, etc. can have alarge negative impact. Modification of the surfaces involved, control ofthe surface properties of the microbes involved, or both can be used toprevent or minimize microbial fouling and/or to enable the efficientremoval of microbial organisms from such processes.

Many commercial disinfectants employing typical quaternary ammoniumbiocides deposited on surfaces to reduce microbial loads tend to leavethe treated surfaces sticky to the touch, which attracts dust anddetritus. This leads to unsightly surfaces that require frequentcleaning and reapplication of the biocide in order to remain effective.

There is a need for concentrated compositions capable of providingstable, but thin and substantially invisible layers or particles over asurface to be treated so as to provide enhanced surface protectiveproperties such as reduced adhesion of soil, reduced biological andenvironmental contamination, and the ability to kill microbes that aredeposited onto the surfaces in a variety of ways (e.g., through airbornecontaminants, food preparation, direct epidermal contact, exposure tobodily fluids, etc.). It would be a further advantage for suchcompositions to simultaneously clean and treat the surfaces to whichthey are applied so that separate cleaning and treatment steps are notrequired.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a compositioncomprising a water-soluble first polyelectrolyte bearing a net cationiccharge or capable of developing a net cationic charge, and awater-soluble second polyelectrolyte bearing a net anionic charge orcapable of developing a net anionic charge. The total polyelectrolyteconcentration of the composition is at least 110 millimolar, and thecomposition is free of coacervates, precipitates, latex particles,synthetic block copolymers, silicone copolymers, cross-linkedpoly(acrylic) and cross-linked water-soluble polyelectrolyte.

Another embodiment of the present invention is directed to a compositioncomprising an oxidant (e.g., an alkali or alkaline earth hypohalite), apolyelectrolyte precursor composition comprising a water-soluble firstpolyelectrolyte bearing a net cationic charge or capable of developing anet cationic charge, and a water-soluble second polyelectrolyte bearinga net anionic charge or capable of developing a net anionic charge. Thetotal polyelectrolyte concentration of the composition is at least 110millimolar, and the composition is free of coacervates, precipitates,latex particles, synthetic block copolymers, silicone copolymers,cross-linked poly(acrylic) and cross-linked water-solublepolyelectrolyte.

Another embodiment of the present invention is directed to an aqueouscomposition consisting essentially of water, a water-soluble firstpolyelectrolyte bearing a net cationic charge or capable of developing anet cationic charge, a water-soluble second polyelectrolyte bearing anet anionic charge or capable of developing a net anionic charge,optionally, one or more of an oxidant, electrolyte, surfactant, solvent,antimicrobial agent, buffer, or any combination thereof. Additionally,the composition may optionally include stain and soil repellants,lubricants, odor control agents, perfumes, fragrances, fragrance releaseagents, bleaching agents, acids, bases, dyes and/or colorants,solubilizing materials, stabilizers, thickeners, defoamers, hydrotropes,cloud point modifiers, preservatives, other polymers, and combinationsthereof. The total polyelectrolyte concentration of the composition isat least 110 millimolar, and the composition is free of coacervates,precipitates, latex particles, synthetic block copolymers, siliconecopolymers, cross-linked poly(acrylic) and cross-linked water-solublepolyelectrolyte.

Further features and advantages of the present invention will becomeapparent to those of ordinary skill in the art in view of the detaileddescription of preferred embodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the drawings located in the specification. It isappreciated that these drawings depict only typical embodiments of theinvention and are therefore not to be considered limiting of its scope.The invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 plots turbidity data of the compositions of Example 14 over time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Definitions

Before describing the present invention in detail, it is to beunderstood that this invention is not limited to particularlyexemplified systems or process parameters that may, of course, vary. Itis also to be understood that the terminology used herein is for thepurpose of describing particular embodiments of the invention only, andis not intended to limit the scope of the invention in any manner.

All publications, patents and patent applications cited herein, whethersupra or infra, are hereby incorporated by reference in their entiretyto the same extent as if each individual publication, patent or patentapplication was specifically and individually indicated to beincorporated by reference.

The term “comprising” which is synonymous with “including,”“containing,” or “characterized by,” is inclusive or open-ended and doesnot exclude additional, unrecited elements or method steps.

The term “consisting essentially of” limits the scope of a claim to thespecified materials or steps “and those that do not materially affectthe basic and novel characteristic(s)” of the claimed invention.

The term “consisting of” as used herein, excludes any element, step, oringredient not specified in the claim.

It must be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an” and “the” include plural referentsunless the content clearly dictates otherwise. Thus, for example,reference to a “surfactant” includes one, two or more such surfactants.

The term water-soluble polymer as used herein means a polymer whichgives an optically clear solution free of precipitates at aconcentration of 0.001 grams per 100 grams of water, preferably 0.01grams/100 grams of water, more preferably 0.1 grams/100 grams of water,and even more preferably 1 gram or more per 100 grams of water, at 25°C.

As used herein, the term “sanitize” shall mean the reduction ofcontaminants in the inanimate environment to levels considered safeaccording to public health ordinance, or that reduces the bacterialpopulation by significant numbers where public health requirements havenot been established. An at least 99% reduction in bacterial populationwithin a 24 hour time period is deemed “significant.” The term“disinfect” may generally refer to the elimination of many or allpathogenic microorganisms on surfaces with the exception of bacterialendospores. The term “sterilize” may refer to the complete eliminationor destruction of all forms of microbial life and which is authorizedunder the applicable regulatory laws to make legal claims as a“sterilant” or to have sterilizing properties or qualities.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the invention pertains. Although a number of methodsand materials similar or equivalent to those described herein can beused in the practice of the present invention, the preferred materialsand methods are described herein.

In the application, effective amounts are generally those amounts listedas the ranges or levels of ingredients in the descriptions, which followhereto. Unless otherwise stated, amounts listed in percentage (“wt %'s”)are in wt % (based on 100 weight % active) of the particular materialpresent in the referenced composition, any remaining percentage beingwater or an aqueous carrier sufficient to account for 100% of thecomposition, unless otherwise noted. For very low weight percentages,the term “ppm” corresponding to parts per million on a weight/weightbasis may be used, noting that 1.0 wt % corresponds to 10,000 ppm.

II. Introduction

According to an embodiment, the PEC precursor solutions of the presentinvention comprise a water-soluble first polyelectrolyte having acationic charge or capable of developing a cationic charge, and a secondwater-soluble polyelectrolyte having an anionic charge or capable ofdeveloping an anionic charge wherein the total polyelectrolyteconcentration of the solution is at least 110 millimolar (mM). Thesolution is advantageously free of coacervates, precipitates, latexparticles, block copolymers, silicone copolymers, cross-linkedpoly(acrylic), and cross-linked water-soluble polyelectrolytes. The PECprecursor solutions may be single phase, clear or slightly coloredtransparent (e.g., bluish) solutions without the presence ofprecipitated particles, suspended solids, flocculates, or other largeaggregates that would cause a hazy or milky appearance.

According to another embodiment, the polyelectrolytes are not selectedfrom the group consisting of polymeric fluorosurfactant derived frompolymerization of a fluorinated oxetane, silicone polymer, anioniclatex, cationic latex, mixtures of polyelectrolytes and a non-polymericmaterial (crosslinker) capable of reacting with the polyelectrolytes toform covalent bonds which crosslink the polyelectrolytes, anionicpolysaccharide containing glucoronic acid, N-acylchitosan with an C₁-C₁₂alkyl group, and/or combinations thereof.

Although there are a variety of materials available that are alreadysurface modified for a specific purpose, there is also a large installedbase of relatively ordinary materials, which surfaces would benefit fromsimple, non-permanent, and invisible modification.

PECs formed through dilution of the present PEC precursor compositionscan provide modification of such surfaces, anchoring of antimicrobialmaterials to surfaces etc., and can function without forming macroscopicfilms. In other words, they may function through adsorption ontosurfaces on a molecular scale, with the adsorbed layers havingdimensions on the order of nanometers. Such adsorbed layers aregenerally invisible to the unaided eye, and do not rely on the formationof permanent chemical bonds between the polymers and the surface, butinstead on a combination of electrostatic and hydrophobic interactionswith the surface.

Solutions of PECs that are active at solid surfaces yet stable duringthe course of use can be produced via methods taught in US2011/0236582(U.S. patent application Ser. No. 12/749,288, incorporated by referenceabove in the priority claim). In one embodiment, the PEC solutionsproduced via such methods may deliver PECs at concentrations (measuredas the total concentration of charged associating groups) of about 100mM or less.

However, in some applications it may be inconvenient to utilize ready touse PEC solutions, that is, in order to deliver PEC solutions to somesurfaces in a variety of applications, it would be preferable to use aconcentrate which can be easily diluted, preferably with a safe solventsuch as water, at or before time of use. Applicants have thusinvestigated compositions and means of producing relatively concentrated“PEC precursor” solutions. Such precursor compositions, which may or maynot comprise PECs themselves, produce PEC solutions upon mixing and/ordilution. The PECs in these diluted compositions can then produce thedesired modification of both inanimate and animate surfaces.

Surprisingly, although aqueous mixtures of polyelectrolytes of oppositecharge may exhibit the undesirable formation of precipitates instead ofsoluble complexes at total polymer concentrations of 50 mM or 100 mM,the inventors have found that it is possible to prepare clear solutionsof the mixed polyelectrolytes at concentrations of at least 110 mM, atleast 120 mM, and of at least 130 mM. This characteristic also exists atmuch higher concentrations, such as at least 500 mM or even at least1000 mM. In other embodiments, the other concentration ranges mayinclude, but not limited to, about 120 mM to about 200 mM, about 130 mMto about 200 mM, about 200 mM to about 400 mM, about 200 mM to about1,000 mM, about 500 mM to about 1,000 mM, about 300 mM to about 1,000mM, about 400 mM to about 1,000 mM, about 500 mM to about 2,000 mM,about 500 mM to about 3,000 mM, about 200 mM to about 3,000 mM, about1,000 mM to about 3,000 mM, about 1,500 mM to about 3,000 mM. Alsosurprisingly, the dilution of these concentrated (PEC precursorsolutions by very large factors, e.g., often 100× or more, yields stablesolutions comprising PECs. This is achieved without any special need forhigh energy or high shear mixing conditions. The stable PEC particlesexhibit dimensions consistent with colloidal solutions, that is,diameters of about 500 nm or less. The stable PEC particles do notflocculate or aggregate into larger particles which may settle out ofsolution, or that would cause a hazy or milky appearance in the absenceof any adjuvants which might be present as particles, such as abrasives,beads, flakes, opacifiers, etc. that may be added. Furthermore, PECsolutions produced via dilution of the PEC precursor solutions may beclear to slightly transparently colored (e.g., blue) in appearance, withan absence of precipitates or coacervates readily detectable by theunaided eye.

The PEC precursor compositions yield solutions comprising stable PECswhen they are diluted with appropriate solvents or solutions containingappropriate adjuvants as described herein. Without being bound bytheory, applicants believe that control of the interactions betweensoluble polyelectrolytes in the precursor solutions ensures delivery oftruly soluble polyelectrolytes upon dilution, which in turn allows theassembly of the PECs via molecular scale interactions between oppositelycharged groups on two or more polyelectrolytes. As a result, it isbelieved that the polymers relax into preferred conformations quickly,without the formation of large precipitates, thus ensuring theproduction of stable PECs of the desired size and composition. Thus, thedilution of PEC precursor solutions to provide stable PECs in solutioneliminates the dependence of PEC formation on the input of large amountsof energy through high shear mixing or other high energy input as taughtin other art. Similarly, there is no need to recover or remove PECcoacervate or precipitate particles or coagulates from the solutions inwhich they are formed prior to use.

In another aspect of the present invention, the PEC precursor solutions,when diluted with water or an aqueous solvent mixture, yield stablesolutions of PECs. The PECs are characterized as having diameters lessthan about 500 nm, preferably less than 200 nm, and even more preferablyless than 100 nm.

In another aspect of the invention, the PECs formed by dilution of a PECprecursor solution modify a solid surface via non-covalent interactionswith the surface, providing one or more benefits selected fromhydrophilic surface modification, hydrophobic surface modification,extended antimicrobial activity of the surface, reduced fouling of thesurface by microorganisms, reduced adhesion of microorganisms to thesurface, stays cleaner longer or easier to clean next time.

In another aspect of the present invention, the PEC precursor solutions,including any optional adjuvants, comprise a first solution which isheld in a first chamber of a dual chamber package, for example, a dualchamber bottle. A second solution comprising a solvent and optionallycomprising other adjuvants may be held in a second chamber of thepackage. The contents of the two chambers of the package may be mixed atthe time of use (for example, through the use of a trigger sprayer withdual dip tubes) to provide a solution of PECs and optional adjuvants.

In an embodiment, the present invention provides PEC precursorcompositions that produce stable polyelectrolyte complexes upon dilutionwith an aqueous solvent.

In an embodiment, the present invention provides PEC precursorcompositions which are compatible with the presence of surfactants,biocides and oxidants.

In an embodiment, the present invention provides PEC precursorcompositions which, upon dilution, provide PECs that result in themodification of inanimate surfaces and deliver benefits such as reducedmicrobial fouling, reduced microbial surface loads, easier subsequentcleaning, simultaneous cleaning and surface treatment, reduced adhesionof oily soils, reduced spotting due to evaporation of water or othervolatile components, all without the need for permanent chemical bondsbetween the PECs and the surfaces, and without the need for theformation of a macroscopic film, that is, by adsorbed layers of PECsthat are invisible to the unaided eye.

In an embodiment, the present invention provides PEC precursorcompositions that eliminate the need for storage of PEC solutions byproviding the formation of PECs on-demand through a simple dilution stepwhich can be achieved through simple manual dilution, an automateddilution and delivery system, or a package design convenient for use byconsumers or professionals.

In an embodiment, the present invention provides PEC precursorcompositions which, upon dilution, provide PECs that can modify thesurfaces of animate objects, such as insects, crop leaves or seeds, orthe surfaces of microbial organisms, (e.g., bacteria, viruses, bacterialspores, or fungal spores). Modification of microbe surfaces via theadsorption of PECs can provide a change in the electrical charge of themicrobes which can then be used for the manipulation or inactivation ofthem in a variety of ways. For example, control of surfacecharacteristics of certain microbes, such as bacterial or fungal spores,may be useful in collection, isolation, identification, or adhesion ofsuch spores.

The aqueous PEC precursor solutions may optionally comprise an adjuvantselected from—an inorganic acid or base, an organic acid or base, a saltof the inorganic acid or base, a salt of the organic acid or base, abuffering agent, an oxidant, a surfactant, or a water-miscible solvent.The precursor solutions themselves may or may not comprise PECs. Wherethey do not comprise PECs, they instead comprise the polyelectrolytes ina soluble state that will assemble to form the PECs upon dilution, i.e.,the precursor solutions are stable, one phase aqueous fluids free ofprecipitates or macroscopic aggregates that may otherwise form due tointeractions between the polyelectrolytes. Subsequent addition of otheradjuvants such as abrasives, opacifiers, etc. may of course yield a morehazy or milky appearance.

The presence of PECs and their dimensions in aqueous solutions may becharacterized via static or dynamic light scattering (DLS). It is wellknown to those skilled in the art that light scattering analyses need tobe conducted with an optimum concentration of scattering particles(PECs, for example). The concentration of polyelectrolytes in many ofthe PEC precursor solutions is often too high for meaningful DLSanalyses. However, dilution of the PEC precursor solution to form thePECs of interest usually results in solutions which are amenable toanalysis by DLS, and hence examples below will demonstrate that stablePECs (generally, having diameters less than 500, preferably less than200, and more preferably less than 100 nm) are formed upon dilution ofthe precursor solutions.

A convenient way to express compositional characteristics of the PECcomposition and precursor is through the value of “R” (described below)which characterizes the charge on the PECs to be formed, and by thedesired dilution factor. The dilution factor can be adjusted over a widerange, depending on the method of dilution to be used. For example, ifthe PEC precursor solutions are to be diluted through use of aconsumer-friendly dual-chamber bottle equipped with a trigger sprayer,the viscosity of the PECs precursor solutions must be sufficiently lowso as to not affect the performance of the package. Alternatively, ifthe PEC precursor solutions are to be diluted by a user via pouring intoordinary tap water (or vice versa), with or without a calibrateddispensing aid such as a bottle cap, the viscosity of the precursorsolution would be less important and could be adjusted to an desiredtarget. As another alternative, the PEC precursor solutions may compriseone liquid stream which is combined with a second liquid stream andordinary water in an apparatus designed to produce treatment, cleaningor disinfecting solutions for use by janitorial personnel.

In another alternative, if the PEC precursor solutions comprise aconcentrated oxidant as an adjuvant, such as sodium hypochlorite atabout 1% to about 10% by weight, the dilution of the precursor solutionmay be achieved by the consumer with ordinary tap water through pouringinto a washing machine, adding the precursor to an automated dispenserincorporated into a washing machine, or by pouring the precursor into avessel containing ordinary tap water.

Aqueous solutions of the anionic and cationic polyelectrolyte stocksthat are to be blended to produce the PEC precursor solutions can beprepared in any manner with conventional equipment, includingdissolution of solid polymers in the aqueous solutions, dilution of aneat polymer melt directly after completion of polymerization via anyconventional means, or dilution of a solution of the polymer obtainedafter polymerization in which the polymerization solvent or solvents aremiscible with the aqueous solutions. Most convenient may be the directuse of polyelectrolyte solutions in aqueous solvents supplied by polymermanufacturers in which the polymer solids level is adjusted such thatthe resulting viscosity of the polyelectrolyte is convenient forconventional liquid handling systems.

In at least some embodiments, the present invention does not contemplatethe use of so-called water-dispersable polyelectrolytes, since it isbelieved that a significant fraction of the ionic groups present in“water-dispersible” polymers or polyelectrolytes may not be readilyaccessible to the oppositely charged ionic groups of another polymer. Ifsome fraction of the ionic groups of the water-dispersible polymers arehidden or occluded within a hydrophobic region of the polymer, or thepolymer itself adopts a given microstructure in a diluent such as water,the assembly conditions of the PECs during dilution are not controlled,and the nature of the PECs produced cannot be controlled. Foressentially the same reasons, at least some embodiments of the presentinvention do not contemplate the use of latex particles of any kind.

In at least some embodiments, the present invention does not contemplatethe use of synthetic block copolymers that can form complex coacervatemicelles. It is believed that complex coacervate micelles, sometimesreferred to as polymeric micelles, are characterized by restriction ofthe charged groups of the polymers to a complex domain that is formed bythe coacervate core, and a corona surrounding the core formed by ahydrophilic and neutral block on at least one of the polymers. Stablecomplex coacervate micelles are only formed if the length of the ionicblock, the length of the hydrophilic block, and the length of theneutral block on the block polymer are appropriate. The formation ofsuch structures is believed to be an undesirable competitive process tothe formation of the PECs formed by the dilution of precursor solutionsas described herein. The PECs of the present invention do not requirethe presence of a hydrophilic and neutral block.

The lack of charged groups on the exterior of the complex coacervatemicelles is a further limitation, since interactions between the chargedgroups of one or both polymers with adjuvants such as surfactants,germicidal quaternary ammonium compounds, or soluble metal ions is notpossible due to the requirement of a neutral hydrophilic block presentin the corona of the complex coacervate micelles. The PECs of thepresent invention, in contrast, when formed by dilution from precursorsolutions, may interact with adjuvants, as desired by the particularapplication.

Random copolymers of a wide range are quite acceptable for use in thepresent invention, as long as they exhibit the appropriate solubility.

The PEC precursor solutions may be made by blending aqueous solutions ofat least one water-soluble polyelectrolyte having a cationic charge orcapable of developing a cationic charge, with an aqueous solution of atleast one water-soluble polyelectrolyte having an anionic charge, orcapable of developing an anionic charge via conventional mixingequipment. For example, a batch tank equipped with an agitator, orpumping through a static mixer may be employed.

The water-soluble polyelectrolytes are typically in soluble form priorto this mixing step so that they will form clear solutions in water at aconcentration of at least 0.1 gram polymer/100 grams of water,preferably 1 gram polymer/100 grams of water, preferably at least 10grams polymer/100 grams water, or more preferably in excess of 50 gramspolymer/100 grams of water at 25° C. In the case of some polymers, anappropriate salt may be formed in order to achieve water solubility, andthus a pre-formed salt of the polymer in water may be used or a polymermay be dissolved in water containing an appropriate acid or base whichforms the water-soluble salt of the polymer.

For example, chitosan is a natural polymer capable of developing acationic charge and exhibits acceptable solubility in water when it isdissolved in water containing an acid, such as citric or acetic acid.Thus, an acid may be present as an adjuvant in the chitosan solutionused in the formation of PEC precursor solutions. The amount of acidrequired may be readily determined by the concentration of the chitosandesired, and by the appearance of the precursor solution formed with ananionic polymer. If the blending of the chitosan with the anionicpolymer results a precursor solution at the desired “R” value having acloudy appearance, then additional acid may be required, either added tothe chitosan stock solution, the anionic polymer solution, or both, inorder to ensure that the final PEC precursor solution remains free ofprecipitates. Alternatively, a solid salt of chitosan, such as thepyrrolidone carboxylic acid salt of chitosan, may be dissolved directlyin water and used.

There are no particular restrictions on the order of addition of thepolyelectrolytes. The agitation needed may depend on the viscosity ofthe polyelectrolyte solutions, but since macroscopic aggregates due toprecipitation of the polymers are to be avoided, the mechanical energyinput may be limited to, and determined by, whatever input is needed toensure complete blending of the two polymer solutions, not by any needfor shear-induced destruction of any macroscopic colloidal aggregates.Thus, in many examples, the maximum practical concentration of thepolyelectrolytes in the precursor solutions may be limited by thesolubility of the individual polyelectrolyte solution stocks, or theviscosity of the resultant clear, one phase precursor solution, strictlyfor mechanical reasons. In general, PEC precursor solutions, in theabsence of particulate adjuvants, will exhibit bulk viscosities lessthan about 1 million centipoise, preferably less than about 10,000centipoise, more preferably less than about 1,000 centipoise.

There are no particular restrictions on the relative molecular weightsof the cationic and anionic polyelectrolytes in the PEC precursorsolutions, contrary to what is taught elsewhere in the art. This isbecause the PECs are assembled via dilution with a second aqueoussolvent which may include optional additives. In other words, theprecursor solutions contain soluble polymers but do not necessarily haveto contain stable PECs themselves.

A convenient way to express the composition of the PEC precursorsolutions and the PECs formed upon dilution of the precursor solutionsis to calculate the ratio of the moles or number of cationic charges tocorresponding moles or number of anionic charges present in thesolution, based on the relative amounts of the polymers added to thebulk solution. Herein below, the parameter “R” is used to denote themolar ratio of cationic (or potentially cationic) groups to that ofanionic (or potentially anionic) groups of the two respectivepolyelectrolytes comprising the associative PECs of the presentinvention, where accordingly:

R=Q ⁺ /Q ⁻

where Q⁺ is the number of moles of cationic charges, Q⁻ is the number ormoles of anionic charges; wherein

Q ⁺=(C _(cationic))*(F _(cationic))*(Q _(cationic))/(M _(cationic))

where C_(cationic) is the concentration of cationic polymer in weightpercent, F_(cationic) is the weight fraction cationic monomer in totalcationic polymer weight, thus being between 0 and 1, Q_(cationic) is thenumber of charges per cationic monomer unit, M_(cationic) is themolecular weight of the monomer unit in polymerized form.Correspondingly:

Q ⁻=(C _(anionic))*(F _(anionic))*(Q _(anionic))/(M _(anionic))

where C_(anionic) is the concentration of anionic polymer in weightpercent, F_(anionic) is the weight fraction anionic monomer in totalanionic polymer weight, thus being between 0 and 1, Q_(anionic) is thenumber of charges per anionic monomer unit, and M_(anionic) is themolecular weight of the monomer unit in polymerized form.

It should be noted that, in the case of polymers comprising multiplecationic (or potentially cationic) or multiple anionic (or potentiallyanionic) groups, the corresponding Q parameter (Q⁺ or Q⁻) would becalculated as a sum of the individual Q values of the same charge.

In the case of so-called amphoteric copolymers, which contain bothcationic (or potentially cationic) and anionic (or potentially anionic)groups, a single polymer would contribute to both the total Q⁺ and Q⁻parameters. Of course, in the case of amphoteric polymers, formation ofa PEC as described herein would still require the presence of a firstamphoteric polymer with a given net charge, for example, cationic, and asecond amphoteric polymer with a given net charge, or that is capable ofdeveloping a net charge, which is opposite to that of the firstamphoteric polymer.

The R values of the PEC precursor solutions may generally be the same asthat of the PECs which are made through the dilution process, i.e.,between about 0.1 and 20.

The PEC precursor solutions may employ water as a solvent. Additionalwater-miscible solvents such as lower alcohols, glycols, glycol ethers,glycol esters, dimethyl sulfoxide, dimethyl formamide, and the like maybe employed. Other liquid materials, such as hydrocarbons, oils, etc.,which are not miscible with water at a concentration of at least 1 gramliquid/100 grams of water at 25° C. may not be considered as componentsof the solvent system in water-based solvent embodiments. That said,such materials may of course be included in the aqueous solutionsthrough the use of surfactants or the addition of certain water-misciblesolvents serving as “coupling agents”.

Selection of adjuvants for incorporation into the precursor solutionsmay depend on the target R value of the PECs to be produced from the PECprecursor solutions, as well as on the type of adjuvants present in theaqueous solution to be used in the dilution of the precursor solutions.Selection should ensure the polyelectrolytes are soluble and thus ableto assemble into PECs in the final diluted solution. A general exampleof adjuvant selection was given above where chitosan was selected as thecationic polyelectrolyte. By way of other general examples, and prior toa discussion of specific PEC precursor solutions, the followingprinciples have also been discovered.

In the case of anionic polyelectrolytes in which the anionic moietiesare carboxylic acids, the anionic polyelectrolyte solution may beprepared from the polyelectrolyte in the acid form, i.e, the acid groupsare in the protonated or non-ionized form or are substantially in theacid form. In other words, the pH of the anionic polyelectrolytesolution prior to mixing with the cationic polyelectrolyte solution isat or below the pKa (or estimated pKa) of the acid groups of the anionicpolyelectrolyte, or at or below about pH 4 in the absence of informationabout the pKa. If the pH of the anionic polyelectrolyte solutionrequires adjustment (e.g., due to minor impurities or method ofpolymerization of the anionic polyelectrolyte), sufficient amounts of anappropriate acid or base may be added.

In the case of anionic polyelectrolytes in which the anionic moietiesare carboxylic acids which are present in the ionized (salt) form, thepH of the polyelectrolyte solution prior to mixing with the cationicpolyelectrolyte solution may be adjusted to near or below the pKa (orestimated pKa or about pH 4 in the absence of information about thepKa.) of the acid groups of the anionic polyelectrolyte via the additionof an effective amount of an appropriate acid or base.

In the case of anionic polyelectrolytes in which the anionic moietiesare carboxylic acids which are present (or in which some fraction of themoieties are present) in the ionized (salt) form, an appropriateelectrolyte may be added to the anionic polyelectrolyte solution in anamount sufficient to produce a clear precursor solution when the anionicpolyelectrolyte solution is mixed with the cationic polyelectrolytesolution.

In the case of anionic polyelectrolytes in which the anionic moietiesare carboxylic acids which are present (or in which some fraction of themoieties are present) in the ionized (salt) form, an appropriateelectrolyte may be added to the cationic polyelectrolyte solution in anamount sufficient to produce a clear precursor solution when the anionicpolyelectrolyte solution is mixed with the cationic polyelectrolytesolution.

In the case of anionic polyelectrolytes in which the anionic moietiesare carboxylic acids which are present (or in which some fraction of themoieties are present) in the ionized (salt) form, an appropriateelectrolyte may be added to both the cationic polyelectrolyte solutionand the anionic polyelectrolyte solution in an amount sufficient toproduce a clear precursor solution when the polyelectrolyte solutionsare mixed.

In the case of anionic polyelectrolytes comprising anionic moieties thatare not carboxylic acids or comprising mixtures of anionic moietiesincluding carboxylic acids and non-carboxylic acid anionic moieties, andin which the pH of the anionic polyelectrolyte solution may not beadjusted below the pKa or estimated pKa of one or more of the anionicmoieties or pH about 4, or in the case in which the desired pH of theanionic polyelectrolyte solution is significantly above the pKa orestimated pKa of the anionic moieties, an appropriate electrolyte may beadded to the anionic polyelectrolyte solution in an amount sufficient toproduce a clear precursor solution when the polyelectrolyte solutionsare mixed.

The “electrolyte” mentioned may be selected from a wide range ofcompounds, including organic acids and bases, inorganic acids or bases,their water-soluble salts, or combinations thereof. In an embodiment,the electrolyte may be an alkali metal salt of hypochlorous acid,alkaline metal salt of hypochlorous acid, or combinations thereof (e.g.,sodium hypochlorite, calcium hypochlorite, or combinations thereof). Anelectrolyte will be deemed appropriate when its use is indifferent to,or known to be compatible with, other adjuvants which may be present inthe final solution of the PECs produced via dilution of the PECprecursor solutions.

III. Suitable Synthetic Polymers

The polymers may be homopolymers or copolymers, and they may be linearor branched. Copolymers may be synthesized by processes expected to leadto statistically random or so-called gradient type copolymers. Incontrast, water-soluble block copolymers are not suitable suitable foruse, since these types of polymers may form aggregates or micelles, inwhich the more hydrophobic block(s) comprise the core of the aggregateor micelles and the more hydrophilic block(s) comprise a “corona” regionin contact with water. It is believed that these self-assembly processesundesirably compete with the formation of PECs.

Although mixtures of water-soluble polymers may be suitable for use, themixtures selected should not comprise block copolymers capable offorming so-called “complex coacervate” micelles through self-assembly.When the polymers are copolymers, the ratio of the two or more monomersmay vary over a wide range, as long as water solubility of the polymeris maintained.

Examples of cationic monomers that may be used include, but are notlimited to diallyldimethyl ammonium chloride, quaternary ammonium saltsof acrylamides, quaternized derivatives of acrylate esters andamides—etc. Monomers capable of developing a cationic charge includeethyleneimine and its derivatives, vinyl imidazole, vinyl pyridineoxide, etc. Combinations of any of the foregoing may also be used.

Additional suitable cationic polymers include homopolymers or copolymersof monomers having a permanent cationic charge or monomers capable offorming a cationic charge in solution upon protonation. Examples ofpermanently cationic monomers include, but are not limited to, diallyldimethyl ammonium salts (such as the chloride salt, referred to hereinas DADMAC) quaternary ammonium salts of substituted acrylamide,methacrylamide, acrylate and methacrylate, such astrimethylammoniumethyl methacrylate, trim ethylammoniumpropylmethacrylamide, trimethylammoniumethyl methacrylate,trimethylammoniumpropyl acrylamide, 2-vinyl N-alkyl quaternarypyridinium, 4-vinyl N-alkyl quaternary pyridinium,4-vinylbenzyltrialkylammonium, 2-vinyl piperidinium, 4-vinylpiperidinium, 3-alkyl 1-vinyl imidazolium, and the ionene class ofinternal cationic monomers. The counterion of the cationic co-monomercan be selected from, for example, chloride, bromide, iodide, hydroxide,phosphate, sulfate, hydrosulfate, ethyl sulfate, methyl sulfate,formate, and acetate.

Examples of monomers that are cationic on protonation include, but arenot limited to, acrylamide, N,N-dimethylacrylamide, N,Ndi-isopropylacryalmide, N-vinylimidazole, N-vinylpyrrolidone, vinylpyridine N-oxide, ethyleneimine, dimethylaminohydroxypropyldiethylenetriamine, aminoethyl methacrylate, dimethylaminopropylmethacrylamide, dimethylaminoethyl acrylate, dimethylaminopropylacrylamide, 2-vinyl pyridine, 4-vinyl pyridine, 2-vinyl piperidine,4-vinylpiperidine, vinyl amine, diallylamine, methyldiallylamine, vinyloxazolidone; vinyl methyoxazolidone, and vinyl caprolactam.

Monomers that are cationic on protonation typically contain a positivecharge over a portion of the pH range of 2-11. Cationic polymers mayalso include other monomers, for example monomers having an unchargedhydrophilic or hydrophobic group. Suitable copolymers containacrylamide, methacrylamide and substituted acrylamides andmethacrylamides, acrylic and methacrylic acid and esters thereof.

The cationic polymer level in the compositions of the present inventionmay typically range from about 0.001 wt % to about 5.0 wt %, or fromabout 0.01 wt % to about 2.5 wt %, or from about 0.01 wt % to about 1.0wt %, or from about 0.1 wt % to about 0.50 wt %.

Examples of anionic monomers that may be used include, but are notlimited to acrylic acid, methacrylic acid, crotonic acid, maleic acid,etc. Phthalic acid and its isomers (e.g., including acid-terminatedpolyesters or condensates of polyesters, polyurethanes or polyamides andethylene, propylene or butylene oxide, etc) may also be suitable foruse. Sulfonate functional monomers such as acrylamidopropyl methanesulfonic acid (AMPS) and the like may also be employed. Combinations ofany of the foregoing may also be used.

Additional suitable anionic polymers include, but are not limited to,polycarboxylate polymers and copolymers of acrylic acid and maleicanhydride, or alkali metal salts thereof, such as the sodium andpotassium salts. Suitable are copolymers of acrylic acid or methacrylicacid with vinyl ethers, such as, for example, vinyl methyl ether, vinylesters, ethylene, propylene and styrene. Also suitable are polymerscontaining monomers capable of taking on an anionic charge in aqueoussolutions when dissolved in water that has been adjusted to anappropriate pH using an acid, a base a buffer or combination thereof.Examples include, but are not limited to, acrylic acid, maleic acid,methacrylic acid, ethacrylic acid, dimethylacrylic acid, maleicanhydride, succinic anhydride, vinylsulfonate, cyanoacrylic acid,methylenemalonic acid, vinylacetic acid, allylacetic acid,ethylidineacetic acid, propylidineacetic acid, crotonic acid, fumaricacid, itaconic acid, sorbic acid, angelic acid, cinnamic acid,styrylacrylic acid, citraconic acid, glutaconic acid, aconitic acid,phenylacrylic acid, acryloxypropionic acid, citraconic acid,vinylbenzoic acid, N-vinylsuccinamidic acid, mesaconic acid,methacroylalanine, acryloylhydroxyglycine, sulfoethyl methacrylate,sulfopropyl acrylate, and sulfoethyl acrylate. Suitable acid monomersalso include styrenesulfonic acid, acrylamide methyl propane sulfonicacid, 2-methacryloyloxy-methane-1-sulfonic acid,3-methacryloyloxy-propane-1-sulfonic acid,3-(vinyloxy)-propane-1-sulfonic acid, ethylenesulfonic acid, vinylsulfuric acid, 4-vinylphenyl sulfuric acid, ethylene phosphonic acid andvinyl phosphoric acid. Examples of commercially available products areSokalan CP5 and PA30 from BASF, ALCOSPERSE 175 and 177 from Alco and LMW45N and SPO2N from Norsohaas. Also suitable are natural anionicpolymers, including but not limited to saccharinic gums such asalginates, xanthates, pectins, carrageenans, guar, carboxymethylcellulose, and scleroglucans.

The anionic polymer level in the compositions of the present inventionmay typically range from about 0.001 wt % to about 5.0 wt %, or fromabout 0.01 wt % to about 2.5 wt %, or from about 0.01 wt % to about 1.0wt %, or from about 0.1 wt % to about 0.50 wt %.

Amphoteric polymers derived from the copolymerization of one or more ofa cationic and an anionic monomer, with or without the presence of athird monomer incapable of developing a charge (nonionic monomers) maysimilarly be employed. Examples of nonionic monomers include, but arenot limited to acrylamide, dimethylacrylamide and other alkylacrylamides which have not been “quaternized” e.g., ethylene, propyleneand/or butylene oxide.

One or both of the polyelectrolytes may be natural or derived fromnatural sources, such as chitosan, quaternized guar, cationicallymodified starches or celluloses. Anionically charged natural ornaturally derived polymers include alginate salts, inulin derivatives,anionically modified starches, etc.

The random copolymers may comprise one or more monomers bearing the samecharge or capable of developing the same charge and one or more monomerswhich are nonionic, i.e, not capable of bearing a charge. Copolymers maybe synthesized by graft processes, resulting in “comb-like” structures.

Preferred copolymers include so-called “hybrid” materials from AkzoNobel such as Alcoguard H 5240. These materials are described ascomprising polysaccharides and synthetic monomers which can function inthe same manner as acrylate/maleate copolymers (i.e., a water-solublepolymer with anionically charged groups) in cleaning formulations.

Water-soluble copolymers derived from a synthetic monomer or monomersthat may be chain terminated with a hydroxyl-containing naturalmaterial, such as a polysaccharide, are preferred. Such materials may besynthesized with ordinary free-radical initiators.

IV. Adjuvants

Surfactants of all types can be used. Where the sustainability of theformulations are of concern, surfactants derived from natural orsustainable sources are preferred.

A. Buffers & Electrolytes

Buffers, buffering agents and pH adjusting agents, when used, include,but are not limited to, organic acids, mineral acids, alkali metal andalkaline earth salts of silicate, metasilicate, polysilicate, borate,carbonate, carbamate, phosphate, polyphosphate, pyrophosphates,triphosphates, tetraphosphates, ammonia, hydroxide, monoethanolamine,monopropanolamine, diethanolamine, dipropanolamine, triethanolamine, and2-amino-2methylpropanol. In one embodiment, preferred buffering agentsinclude but are not limited to; dicarboxylic acids, such as, succinicacid and glutaric acid. Some suitable nitrogen-containing bufferingagents are amino acids such as lysine or lower alcohol amines likemono-, di-, and tri-ethanolamine. Other nitrogen-containing bufferingagents are Tri(hydroxymethyl) amino methane (HOCH₂)₃CNH₃ (TRIS),2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-propanol,2-amino-2-methyl-1,3-propanol, disodium glutamate, N-methyldiethanolamide, 2-dimethylamino-2-methylpropanol (DMAMP),1,3-bis(methylamine)-cyclohexane, 1,3-diamino-propanolN,N′-tetra-methyl-1,3-diamino-2-propanol, N,N-bis(2-hydroxyethyl)glycine(bicine) and N-tris(hydroxymethyl)methyl glycine (tricine). Othersuitable buffers include ammonium carbamate, citric acid, and aceticacid. Mixtures of any of the above may also be acceptable. Usefulinorganic buffers/alkalinity sources include ammonia, the alkali metalcarbonates and alkali metal phosphates, e.g., sodium carbonate, sodiumpolyphosphate.

In one embodiment, when a hypohalous acid (e.g., hypochlorous acid) isused, an acid may be beneficial to stabilize the pH and maintain thedesired ratio of hypochlorous acid to hypochlorite anion. In some cases,the acid may be added to a solution containing hypochlorite anion toconvert this anion to hypochlorous acid. An acid may also be used tocontrol the formation of chlorine dioxide from a chlorite salt. Acid mayalso be used with peroxygen compounds to control stability orreactivity. Acids may also be added for cleaning and removal of soilssuch as hard water deposits and rust. Exemplary acids include, but arenot limited to inorganic acids such as hydrochloric acid or sulfuricacid; and organic acids such as sulfonic acid, polysulfonic acid,monocarboxylic acid, dicarboxylic acid, polycarboxylic acid, acidsulfate, acid phosphate, phosphonic acid, aminocarboxylic acid andmixtures thereof. Specific examples of acids, include but are notlimited to, acetic acid, succinic acid, glutaric acid, adipic acid,polyacrylic acid, sodium bisulfate, 3-pyridine sulfonic acid, dodecylbenzene sulfonic acid, polyacrylic acid, and mixtures thereof. Sodium,potassium and any other salt of any of these acids or mixtures thereofmay also be included to achieve the desired pH and create a buffersystem that resists changes in pH.

Buffers and electrolytes “screen” the interactions between thepolyelectrolytes of the present invention, and thus may be used tomodify phase behavior, such as preparing formulations “close” to acoacervate phase boundary, which may be useful where the complexesbecome sufficiently large (up to about 500 nm diameter) or high enoughin total molecular weight to exhibit enhanced adsorption onto surfaces.Any suitable electrolyte salt known in the art may be used to controlionic strength and/or pH of the final formulations. When used herein thebuffer or electrolyte salt is preferably present at a concentration offrom about 0.001 wt % to about 20 wt %, more preferably 0.05 wt % toabout 1 wt %, even more preferably from about 0.05 wt % to about 0.5 wt%, and most preferably 0.1 wt % to about 0.5 wt %.

B. Oxidants

The compositions of the present invention can also, optionally, containoxidants and/or bleaching agents. Preferred oxidants include, but arenot limited to, hydrogen peroxide, alkaline metal salts and/or alkalineearth metal salts of hypochlorous acid, hypochlorous acid, solubilizedchlorine, any source of free chlorine, solubilized chlorine dioxide,acidic sodium chlorite, active chlorine generating compounds, activeoxygen generating compounds, chlorine-dioxide generating compounds,solubilized ozone, sodium potassium peroxysulfate, sodium perborate, andcombinations thereof. The oxidant can be present at a level of from0.001% to 10%, or from 0.01% to 10%, or from 0.1% to 5% by weight, orfrom 0.5% to 2.5% by weight.

C. Antimicrobial Agents

The compositions of the present invention can also, optionally, containantimicrobial (germicidal) agents or biocidal agents. Such antimicrobialagents can include, but are not limited to, alcohols, chlorinatedhydrocarbons, organometallics, halogen-releasing compounds, metallicsalts, pine oil, organic sulfur compounds, iodine compounds, silvernitrate, quaternary ammonium compounds (quats), chlorhexidine salts,and/or phenolics. Antimicrobial agents suitable for use in thecompositions of the present invention are described in U.S. Pat. Nos.5,686,089; 5,681,802, 5,607,980, 4,714,563; 4,163,800; 3,835,057; and3,152,181, each of which is herein incorporated by reference in itsentirety. Also useful as antimicrobial agents are the so-called“natural” antibacterial actives, referred to as natural essential oils.These actives derive their names from their natural occurrence inplants. Suitable antimicrobial agents include alkyl alpha-hydroxyacids,aralkyl and aryl alpha-hydroxyacids, polyhydroxy alpha-hydroxyacids,polycarboxylic alpha-hydroxyacids, alpha-hydroxyacid related compounds,alpha-ketoacids and related compounds, and other related compoundsincluding their lactone forms. Preferred antimicrobial agents include,but are not limited to, alcohols, chlorinated hydrocarbons,organometallics, halogen-releasing compounds, metallic salts, pine oil,organic sulfur compounds, iodine, compounds, antimicrobial metal cationsand/or antimicrobial metal cation-releasing compounds, chitosan,quaternary alkyl ammonium biocides, phenolics, germicidal oxidants,germicidal essential oils, germicidal botanical extracts,alpha-hydroxycarboxylic acids, and combinations thereof. Whenincorporated herein the antimicrobial agent is preferably present at aconcentration of from about 0.001 wt % to about 10 wt %, more preferably0.05 wt % to about 1 wt %, even more preferably from about 0.05 wt % toabout 0.5 wt %, and most preferably 0.1 wt % to about 0.5 wt %.

D. Solvents

Water may be used as a solvent alone, or in combination with anysuitable organic solvents. Such solvents may include, but are notlimited to, C₁₋₆ alkanols, C₁₋₆ diols, C₁₋₁₀ alkyl ethers of alkyleneglycols, C₃₋₂₄ alkylene glycol ethers, polyalkylene glycols, short chaincarboxylic acids, short chain esters, isoparafinic hydrocarbons, mineralspirits, alkylaromatics, terpenes, terpene derivatives, terpenoids,terpenoid derivatives, formaldehyde, and pyrrolidones. Alkanols include,but are not limited to, methanol, ethanol, n-propanol, isopropanol,butanol, pentanol, and hexanol, and isomers thereof. In one embodimentof the invention, water comprises at least 80% of the composition byweight, or at least 90% of the composition by weight or at least 95% ofthe composition by weight. In another embodiment of the invention, theorganic solvents can be present at a level of from 0.001% to 10%, orfrom 0.01% to 10%, or from 0.1% to 5% by weight, or from 1% to 2.5% byweight.

E. Surfactants

The compositions of the present invention may contain surfactantsselected from nonionic, anionic, cationic, ampholytic, amphoteric andzwitterionic surfactants and mixtures thereof. A typical listing ofanionic, ampholytic, and zwitterionic classes, and species of thesesurfactants, is given in U.S. Pat. No. 3,929,678 to Laughlin andHeuring. A list of suitable cationic surfactants is given in U.S. Pat.No. 4,259,217 to Murphy. The surfactants may be present at a level offrom about 0% to 90%, or from about 0.001% to 50%, or from about 0.01%to 25% by weight. Alternatively, surfactants may be present at a levelof from about 0.1 to 10% by weight, or from about 0.1 to 5% by weight,or from about 0.1 to 1% by weight.

F. Additional Adjuvants

The compositions of the present invention may optionally contain one ormore of the following adjuncts: stain and soil repellants, lubricants,odor control agents, perfumes, fragrances and fragrance release agents,and bleaching agents. Other adjuncts include, but are not limited to,acids, bases, dyes and/or colorants, solubilizing materials,stabilizers, thickeners, defoamers, hydrotropes, cloud point modifiers,preservatives, chelating agents, water-immiscible solvents, enzymes andother polymers.

The compositions of the present invention may be used by distributing,e.g., by placing the aqueous solution into a dispensing means,preferably a spray dispenser and spraying an effective amount onto thedesired surface or article. An effective amount as defined herein meansan amount sufficient to modify the surface of the article to achieve thedesired benefit, for example, but not limited to soil repellency,cleaning and/or disinfectancy. Distribution can be achieved by using aspray device, such as a trigger sprayer or aerosol, or by other meansincluding, but not limited to a roller, a pad, a wipe or wipingimplement, sponge, etc.

In another embodiment, a surface, an article or a device may be treatedwith the compositions of the present invention by immersing them orexposing the desired portion of the article or device to be treated to abulk liquid solution containing the described PECs in the form of atreatment composition. Suitable immersion methods include baths, dippingtanks, wet padding and wet rolling application means common to the art.Such means are also suitable for forming premoistened wipes wherein acarrier substrate such as a woven material (cloth, towel, etc.) or anon-woven material (paper towel, tissue, toilet tissue, bandage) thatmay be dipped or padded with the described PEC compositions.

V. Measurement of Particle Sizes and Zeta Potentials

The diameters of the PECs (in nanometers) and their zeta potentials weremeasured with a Zetasizer ZS (Malvern Instruments). This instrumentemploys DLS, also known as Photon Correlation spectroscopy, to determinethe diameters of colloidal particles in the range from about 0.1 nm toabout 10000 nm.

The Zetasizer ZS instrument offers a range of default parameters whichcan be used in the calculation of particle diameters from the raw data(known as the correlation function or autocorrelation function). Thediameters of the PECs reported herein were determined using a simplecalculation model, in which the optical properties of the PECs wereassumed to be similar to spherical particles of polystyrene latexparticles, a common calibration standard used for more complex DLSexperiments. In addition, the software package supplied with theZetasizer provides automated analysis of the quality of the measurementsmade, in the form of “Expert Advice”. The diameters described herein(specifically what is known as the “Z” average particle diameter) werecalculated from raw data that met “Expert Advice” standards consistentwith acceptable results, unless otherwise noted. In other words, thesimplest set of default measurement conditions and calculationparameters were used to calculate the diameters of all of the PECsdescribed herein, in order to facilitate direct comparison of PECs basedon a variety of polymers, and avoiding the use of complex models of thescattering which could complicate or prevent comparisons of thediameters of PECs of differing chemical composition. Those skilled inthe art will appreciate the particularly simple approach taken here, andrealize that it is a valid approach to comparing and characterizing thePECs.

The Zetasizer ZS instrument instrument calculates the zeta potential ofcolloidal particles from measurements of the electrophoretic mobility,determined via a Doppler laser velocity measurement. The relationshipbetween the electrophoretic mobility (a measurement of the velocity of acharged colloidal particle moving in an electric field) and the zetapotential (electric charge, expressed in units of millivolts) is wellknown. As in the particle size measurements, to facilitate directcomparison of PECs based on a variety of polymers, the simplest set ofdefault measurement conditions were used. In other words, the aggregateswere assumed to behave as polystyrene latex particles, and theSmoluchowski model relating the electrophoretic mobility and the zetapotential was used in all calculations. Unless otherwise noted, the meanzeta potentials described herein were calculated from raw data that met“Expert Advice” standards consistent with acceptable results. PECsbearing a net cationic (positive) charge will exhibit positive values ofthe zeta potential (in mV), while those bearing a net anionic (negative)charge will exhibit negative values of the zeta potential (in mV).

VI. Quartz Crystal Microgravimetry with Dissipation

Quartz Crystal Microgravimetry with Dissipation (QCM-D) offers an idealexperimental setup for fast, flow-cell or static measurements ofadsorption at the solid-liquid interface. Applicants have used QCM-D toquantify adsorption of PECs produced via dilution of PECs precursorsolutions at the solid-solution interface, where the solid is a silicondioxide sensor surface (QSX 303 QCM-D sensors, obtained from Q-Sense.)

QCM-D measurements utilize a thin quartz disc sensor sandwiched betweena pair of electrodes. When AC voltage is applied, the piezoelectricquartz crystal oscillates. The resonance frequency (f) of the crystaldepends on the total oscillating mass, including water coupled to theoscillation. f decreases when a thin film is attached to the sensorcrystal. This decrease is proportional to mass of film, if the film isthin and rigid. The mass (m) of the adhering layer can be calculated byusing the Sauerbrey relation, Δm=−ΔfC/n, where C=17.7 ng Hz⁻¹ cm⁻² for a˜5 MHz quartz crystal and n=1, 3, 5, 7, 9, 11 is the overtone number(see Sauerbrey, G. Z. Phys. 1959, 15, 206-222). Soft, viscoelastic filmsdo not fully couple to crystal oscillation, and for such films, theSauerbrey relation underestimates mass on surface. Soft films dampen theoscillation of the crystal. This damping or dissipation (D) of thecrystal's oscillation reveals the film's viscoelasticity. D is definedas D=E_(dissipated) (2πE_(stored)), where E_(dissipated) is dissipatedor lost energy during one oscillation cycle, and E_(stored) is the totalamount of energy stored in the oscillator. Soft films, dissipatingfilms, or films from viscoelastic fluids should be modeled, and shouldnot be analyzed by the Sauerbrey relation.

Q-Sense, the manufacturer of the instrument used in our measurements,recommends use of the Sauerbrey relation if ΔD≦2×10⁻⁶. Thus, the resultsdescribed herein exclusively use the Sauerbrey relation, as the adsorbedlayers delivered by PECs were not viscoelastic.

QCM-D was performed using a Q-Sense E4, which is designed to run foursimultaneous experiments. In this work, four identical experiments wereperformed simultaneously. Prior to use, sensors were cleaned in plasmacleaner (Harrick PDC-32G) at medium RF, for 20 minutes. Clean, drysensors were mounted in the four flow-through modules, and theexperimental setup was equilibrated at 25.0±0.02° C. with ultrapurewater or buffer flow at 150 μL/min until the frequency and dissipationbaselines were level. Frequencies were monitored such that drift of 3rdharmonic was ≦1.5 Hz/hr. Each experiment began with flow-through ofbuffer at 150 μL/min for 10 minutes to establish a reference zerobaseline. After 10 minutes, the pump was stopped briefly in order toswitch from buffer to PEC solution. PEC solution was pumped through themodules until adsorption plateaued. Thereafter, the pump was stopped andthe inflow solution was switched back to buffer for rinsing. After eachquadrupled experiment, 50/50 ethanol/water was pumped over sensors toremove PECs from flow-through surfaces.

Data reproducibility was checked by four simultaneous experiments, usingsame solution container for all four inlet tubing inputs. Thetemperature of the measuring chamber was kept at 25.0° C.±0.02° C. witha Peltier unit. The average relative humidity was 45%, and the averagelab temperature was 21° C. The data from overtone frequencies 3, 5, 7,9, and 11 was averaged over all self-consistent sensor outputs.

VII. Examples Example 1 PEC Precursor Solutions ComprisingPoly(Diallyldimethyl Ammonium Chloride) (DADMAC) and Poly(Acrylic Acid)(PAA) and DLS Characterization of PECs Produced by Dilution

Table 1.1 summarizes the compositions of several PEC precursor solutionsin which the R value was varied from significantly less than 1, to 1.33and to significantly greater than 1. In addition, the compositions weredesigned to have acidic pH levels, in order to be compatible withdiluents comprising sources of hypochlorite ions such that the finalaqueous solutions could, if desired, comprise hypochlorous acid.

The PEC precursor solutions comprising DADMAC and PAA were prepared inthe following manner. An aqueous solution of DADMAC (40% polymeractives) was weighed and dispensed into a glass beaker followed by theappropriate volume of water required to achieve the desired totalpolymer concentration. This solution was thoroughly mixed using simpleagitation. Finally, an aqueous solution of PAA (26% polymer actives) wasweighed and added to the solution followed by mixing by simpleagitation. The resulting precursor solutions were viscous, clear toclear-blue liquids without insoluble macroscopic particles. The totalpolymer concentration is defined by summing the moles of the repeatunits of DADMAC and PAA polymers present in the precursor solutions.That is,

Concentration=wt % DADMAC/MW_(DADMAC)+wt % PAA/MW_(PAA)

where MW_(DADMAC) and MW_(PAA) are the molecular weight of the repeatunits of DADMAC and PAA, respectively.

The diluted solutions comprising PECs can be prepared by diluting thePEC precursor solutions in any convenient manner. In this example, theprecursor solutions were dispensed into a beaker, followed by additionof a volume of water or aqueous diluent to produce the dilutedcompositions comprising PECs. Alternatively, the order can be reversedwherein the precursor solution can be directly added to an appropriatevolume of water or an aqueous diluent. In this example the solution wasmixed via a magnetic stirbar for about 5 minutes to produce the dilutedsolutions comprising PECs. The diluted solutions were free ofprecipitates, free of flocculant, and suitable for analysis via dynamiclight scattering, as described.

As described herein, the R value of the PEC precursor solutions may beadjusted to control the R value of the final PECs produced upondilution. By controlling the R value of the PECs, the composition of thePECs, and hence the net charge (as measured by the mean zeta potential)on the PECs produced by dilution may be controlled. This control of thecompositions and zeta potential of the PECs produced by dilution isachieved because the PEC precursor solutions comprise thepolyelectrolytes in completely soluble form, free of coacervate orprecipitates, which may be achieved via the methods taught herein.

TABLE 1.1 PEC Precursor Compositions Total polymer Formulation DADMAC,PAA, Water, DADMAC, PAA, concentration, Name grams grams grams wt % wt %mM pH R value Precipitate DADPAA 1 13.53 18.14 18.33 10.7 9.5 2000 2.130.5 No DADPAA 2 32.48 5.44 12.08 25.8 2.8 2000 2.67 4.0 No DADPAA 3 4.9211.68 33.40 18.4 6.1 2000 2.33 1.33 No Notes: DADMAC (Floquat 4540, SNFInc., aqueous solution with 40% polymer actives), PAA (Aquatreat AR4,Akzo Nobel, aqueous solution with 26% polymer actives)

TABLE 1.2 PEC Compositions Produced Via Dilution of PEC Precursors fromTable 1.1 Total polymer Formulation Precursor Precursor, Water, DADMAC,PAA, concentration, Name Composition grams grams mM mM mM pH DADPAA 4DADPAA 1 0.38 499.63 0.5 1.0 1.5 3.62 DADPAA 5 DADPAA 1 0.38 499.63 0.51.0 1.5 3.57 DADPAA 6 DADPAA 1 0.38 499.63 0.5 1.0 1.5 3.59 DADPAA 7DADPAA 2 0.38 499.63 1.2 0.3 1.5 4.01 DADPAA 8 DADPAA 3 0.38 499.63 0.860.64 1.5 3.70

TABLE 1.3 Z-average diameters and zeta potentials of PECs Produced ViaDilution of Precursor Compositions from Table 1.1 Total PolymerZ-average Zeta Formulation R concentration, diameter, Potential, Namevalue mM nm mV Comments DADPAA 4 0.5 1.5 92.80 (n = 3) +41.7 Stepdiluted, water added to precursor DADPAA 5 0.5 1.5 93.28 (n = 3) +37.2Step diluted, water added to precursor DADPAA 7 4.0 1.5 173.4 (n = 3)+39.4 water added to precursor DADPAA 8 1.33 1.5 180.0 (n = 3) +57.0water added to precursor

The results in Table 1.3 indicate that PECs with average diameters thatwill result in colloidal stability (less than 500 nm, more preferablyless than 250 nm, even more preferably less than 100 nm can be formedupon dilution of PECs precursor solutions. Aqueous solutions comprisingPECs at very low total polymer concentrations, in this example at only1.5 mM, are very effective in the modification of a wide variety ofsurfaces, both inanimate (glass, tile, fabrics) and animate (bacterialspores, virus particles), due to the rapid adsorption of PECs onto suchsurfaces. The PEC precursor solutions of this example thus show how veryconvenient formulations that provide aqueous PECs upon very largedilution factors (2000 mM to 1.5 mM total polymer dilution, or 1333.3times dilution) may be achieved. Formulation DADPAA 4 was diluted insteps, from 2000 mM to 250 mM to 50 mM to 1.5 mM. Formulation DADPAA 5was also diluted in steps, from 2000 mM to 250 mM to 1.5 mM.Formulations DAD PAA 6-8 were diluted directly from 2000 mM to 1.5 mM.

The results in Table 1.3 also show the surprising result that stablePECs, even with compositions described by R values less than 1.0, mayexhibit positive (cationic) values of the mean zeta potential. This isachieved in this example by ensuring the pH of the diluted aqueoussolutions comprising the PECs was sufficiently acidic (about pH 3.6) tocause a significant fraction of the carboxylic acid groups of theanionic polymer (here PAA) to exist in their protonated (non-ionized)form, resulting in the net zeta potential of the PECs to be determinedby the presence of the cationic groups of the DADMAC polymer chainsincorporated in the PECs.

The inventors speculate, without being bound by theory, that the use ofPEC precursor solutions comprising fully soluble polyelectrolytes, whichmay be achieved as taught herein, allows the controlled and rapidformation of PECs during the dilution process because thepolyelectrolytes are initially fully soluble, relatively flexible, andthus able to easily relax into conformations favoring electrostaticinteractions between the charged groups on the polyelectrolytes ofopposite charge, forming PECs of appropriately small size upon simpledilution, without the requirement for large amounts of mechanical energyinput. In other words, the PECs are assembled rapidly during thedilution process, and then are separated from one another upon furtherdilution, as opposed to the formation of insoluble macroscopic particlescomprising the oppositely charged polyelectrolytes, which then must beprocessed to reduce the average particle size through extremely highshear mixing or additional steps comprising recovery of the insolublePEC particles.

Example 2 Compositions of PEC Precursor Solutions and DLSCharacterization of PECs Produced by Dilution Comprising Chitosan (aNatural Polymer) and Poly(Acrylic Acid) (PAA)

Details of exemplary PEC precursor solutions comprising a naturalpolymer (chitosan) and PAA at R values both less than and significantlygreater than 1.0 are summarized in Table 2.1. In order to ensure thesolubility of chitosan in the precursor solutions, the pH was adjustedto be acidic, which causes the formation of cationic charges on theamine groups of the chitosan. Since PAA is soluble in aqueous solutionsin its protonated acid form, the PECs precursor solutions were clear andfree of coacervates or precipitates.

Precursor solutions of chitosan and PAA can be prepared in a mannersimilar to PAA and DADMAC solutions. Chitosan, when sourced as a solidpowder, may first be dissolved into an acidic aqueous stock solution(e.g., hydrochloric acid or citric acid). In this example, the chitosanstock was then diluted with water, and the pH adjusted to less than 3.0,followed by addition of the aqueous solution of PAA. Mixing with simpleagitation completed the preparation. Precipitation of the precursorsolutions can be avoided by maintaining an acidic pH. In this example,no precipitates were observed if the pH of the precursor solution wasbelow 3.5.

Diluted solutions comprising PECs can be prepared by adding a volume ofthe precursor solutions into an appropriate volume of water required toreach the final total polymer concentration desired. Continuousagitation or mixing during the dilution aids in the formation ofcolloidal stable PECs. Once the solution has been thoroughly mixed, thepH can be adjusted by adding acid or base depending on the desired pHvalue. Precipitation within the diluted solutions comprising PECs can beavoided by maintaining an acidic pH. In this example, in which chitosanis the polyelectrolyte capable of developing a cationic charge at acidicpH values, no precipitates were observed where the pH was below 3.5.

TABLE 2.1 PEC Precursor Compositions Comprising Chitosan and PAA Totalpolymer Formulation Chitosan PAA, HCl, Water, Chitosan, PAA,concentration, Name grams grams grams grams wt % wt % mM pH R valuePrecipitate CPAA 1 4.27 0.91 1.00 13.82 1.3 1.2 250 3.46 0.5 No CPAA 210.26 0.27 1.00 8.47 3.2 0.44 250 3.44 4.0 No CPAA 3 15.81 3.36 1.00 —4.9 4.4 925 3.27 0.5 No CPAA 4 18.67 0.50 1.00 — 5.8 0.65 455 3.20 4.0No Notes: Chitosan, (Hydagen HCMF, Cognis, 6% acidic solution: 2.0 gramschitosan, 10.0 grams 1.0M HCl, 20.0 grams water), PAA (Aquatreat AR4,Akzo Nobel, aqueous solution with 26% polymer actives)

TABLE 2.2 PEC Compositions Produced Via Dilution of PrecursorCompositions from Table 2.1 Total polymer Formulation PrecursorPrecursor, HCl, Water, Chitosan, PAA, concentration, Name Compositiongrams grams grams mM mM mM R value pH Precipitate CPAA 5 CPAA 1 1.201.00 197.80 0.5 1.0 1.5 0.5 3.5 No CPAA 6 CPAA 2 1.20 1.00 197.80 1.20.3 1.5 4.0 3.4 No CPAA 7 CPAA 3 1.32 1.34 198.34 0.5 1.0 1.5 0.5 3.3 NoCPAA 8 CPAA 4 1.66 1.34 198.00 1.2 0.3 1.5 4.0 3.2 No CPAA 9 CPAA 3 0.32— 199.68 0.5 1.0 1.5 0.5 4.0 Yes CPAA 10 CPAA 4 0.66 — 199.34 1.2 0.31.5 4.0 4.0 Yes

TABLE 2.3 Z-average diameters and zeta potentials of PECs Produced ViaDilution of Precursor Compositions from Table 2.1 Total PolymerZ-average Zeta Formulation R concentration, diameter, Potential, Namevalue mM nm mV Comments CPAA 5 0.5 1.5 177.3 (n = 3) +34.5 Precursoradded into water CPAA 6 4.0 1.5 295.7 (n = 3) +52.3 Precursor added intowater CPAA 7 0.5 1.5 545.5 (n = 3) +39.7 Precursor added into water CPAA8 4.0 1.5 214.0 (n = 3) +53.5 Precursor added into water

The results in Table 2.3 indicate that PEC precursor solutionscomprising chitosan, a polymer comprising amine groups capable ofdeveloping a cationic charge at acidic pH values, and PAA, a polymercomprising carboxylic acid groups, yield stable PECs when diluted. As inExample 1, the PECs formed from precursor solutions with R values ofless than 1.0 exhibit a cationic charge due to the presence of cationiccharges on the chitosan polymer chains and the presence of the acid formof the anionic groups on the PAA chains when the desired pH of thediluted PECs solution is controlled to be acidic.

The results in Table 2.3 also illustrate one way to adjust the size ofthe PECs formed by dilution of a precursor solution. Althoughformulation CPAA 3 is a clear solution free of coacervates andprecipitates, the Z-average diameter of the PECs formed from dilutionwas larger (545.5 nm) than may be preferred for optimum colloidalstability. Reduction of the total polymer concentration in the precursorsolution at the same R value (Formulation CPAA 1) yields smaller PECs ofsimilar zeta potential upon dilution to the same desired polymerconcentration. Thus, the total polymer concentration of the precursorsolution may be adjusted, without other changes, in order to control thesize of the PECs formed upon dilution, which in turn determines therelative colloidal stability of the PECs formed via dilution.

The results in Table 2.3 also indicate that the formation of PECs viadilution of precursor solutions does not depend on the details of themanner of dilution. In other words, the dilution of the precursors inExample 2 was made by dropping an appropriate volume of the precursorsolution into water under simple agitation provided by a magneticstirbar. This is in contrast to how dilution was achieved in Example 1,where a small volume of the precursor solution was placed in a beaker,followed by a stirbar to provide moderate agitation, and then anappropriate volume of water was quickly added.

Example 3 PEC Precursor Solutions Comprising Lupasol and Poly(AcrylicAcid) (PAA) and DLS Characterization of PECs Produced by Dilution

Precursor solutions of Lupasol (a synthetic polymer) and PAA can beprepared in a manner similar to PAA and DADMAC solutions. Theappropriate amount of Lupasol was first diluted into an acidic solutionof sodium chloride and then combined with an appropriate amount of anaqueous solution of PAA. Mixing with simple agitation completed thepreparation. Diluted solutions comprising PECs were prepared by adding avolume of the precursor solutions into an appropriate volume of waterrequired to reach the ultimate total polymer concentration desired.Simple mixing during the dilution was achieved via a magnetic stirbar.Once the solution has been thoroughly mixed, the pH can be adjusted byadding acid or base depending on the desired pH value. Precipitation ofthe precursor solutions can be avoided by maintaining an acidic pH. Inthis example, no precipitates were observed if the pH of the precursorsolution was below 3.5. Precipitation of the precursor solutions canalso be avoided by the addition of excess electrolyte. In this example,no precipitates were observed if 500 mM sodium chloride was present inthe precursor solution.

As shown in Table 3.1, a PEC precursor solution designed to yield PECsin an acidic solution comprising Lupasol (which develops a cationiccharge at acidic pH values) and PAA can be produced through the additionof an electrolyte (NaCl) to the precursor solution.

TABLE 3.1 PECs Precursor Compositions Total polymer Formulation LupasolPAA, NaCl, HCl, Water, Lupasol, PAA, concentration, NaCl, R Name gramsgrams grams grams grams wt % wt % mM mM pH value Precipitate LupPAA 11.44 9.07 2.00 3.00 4.49 1.33% 1.18% 250 500 2.34 0.5 No LupPAA 2 3.452.72 2.00 3.00 8.83 3.18% 0.36% 250 500 2.51 4.0 No LupPAA 3 1.44 9.072.00 — 7.49 1.33% 1.18% 250 500 3.84 0.5 Yes LupPAA 4 3.45 2.72 2.00 —11.83 3.18% 0.36% 250 500 9.83 4.0 Yes LupPAA 5 1.44 9.07 — 3.00 9.491.33% 1.18% 250 0 2.25 0.5 Yes LupPAA 6 3.45 2.72 — 3.00 13.83 3.18%0.36% 250 0 2.52 4.0 No Notes: Lupasol (Lupasol P, BASF, aqueoussolution used at 5% polymer actives), PAA (Aquatreat AR4, Akzo Nobel,aqueous solution with 2.6% polymer actives), NaCl (5.0M aqueoussolution), HCl (1.0M aqueous solution)

TABLE 3.2 PEC Compositions Produced Via Dilution of PrecursorCompositions from Table 3.1 Total polymer Formulation PrecursorPrecursor, Water, Lupasol, PAA, concentration, R Name Composition gramsgrams mM mM mM value pH Precipitate LupPAA 7 LupPAA 1 0.60 99.40 0.5 1.01.5 0.5 3.39 No LupPAA 8 LupPAA 2 0.60 99.40 1.2 0.3 1.5 4.0 3.49 No

TABLE 3.3 Z-average diameter and zeta potential of PECs Produced ViaDilution of Precursor Compositions from Table 3.1 Total PolymerZ-average Zeta Formulation R concentration, diameter, Potential, Namevalue mM nm mV Comments LupPAA 6 4.0 1.5 57.13 +43.9 Precursor addedinto water

The results in Table 3.3 show that a PEC precursor solution comprising apolymer capable of developing a cationic charge (the branchedpolyethyleneimine polymer Lupasol P) and a polymer capable of developingan anionic charge (PAA) yields a stable PEC upon dilution. Since the Rvalue is greater than 1.0, the PECs formed upon dilution exhibit acationic (positive) zeta potential, as expected.

Example 4 Compositions of PECs Precursor Solution and DLSCharacterization of PECs Produced by Dilution Comprising DADMAC andPoly(Vinyl Sulfate)

Precursor solutions of DADMAC and poly(vinyl sulfate) (PVS), apolyelectrolyte with anionic charged groups (sulfate groups), can beprepared in a manner similar to PAA and DADMAC solutions. An aqueoussolution of DADMAC was first diluted in the appropriate of amount waterfollowed by the addition of the appropriate amount of an aqueoussolution of poly(vinyl sulfate). Mixing with simple agitation completedthe preparation. Diluted solutions comprising PECs can be prepared byadding a volume of the precursor solutions, with simple stirring, intothe appropriate volume of water required to reach the ultimate totalpolymer concentration desired. Optionally, an electrolyte or oxidant canbe added (e.g., added to the water used for the dilution step). Once thesolution has been thoroughly mixed, the pH can be adjusted by addingacid or base depending on the desired pH value.

Sodium chloride was used as a substitute for sodium hypochlorite in theformulations of Example 4, in order to ensure measurement of the zetapotential of the PECs produced via dilution was not compromised by thepresence of the oxidant.

The PEC precursor compositions summarized in Table 4.1 show that clear,stable precursor solutions may comprise DADMAC, a polyelectrolyte withcationic charges due to quaternary ammonium groups, which do not exhibita dependence on the pH of the aqueous precursor solution. Theseprecursor compositions also comprise poly(vinyl sulfate), apolyelectrolyte with sulfate groups, which are also not particularlysensitive to the pH of the aqueous solutions, i.e., the pKa of thesulfate groups is estimated to be significantly less than 4, and lessthan about 2.

PEC precursor solutions comprising DADMAC and PVS, with R values greaterthan 1.0, are especially suitable for dilution with aqueous solutionscomprising sodium hypochlorite, to provide PECs in the diluted aqueoussolutions in combination with the hypochlorite ion and hypochlorousacid, which can provide rapid stain removal and antimicrobial propertiesuseful in cleaning healthcare facilities or as additives in launderingprocesses done by consumers.

TABLE 4.1 PECs Precursor Compositions Total polymer Formulation DADMAC,PVS, Water, DADMAC, PVS, concentration, R Name grams grams grams wt % wt% mM value Precipitate DADPVS 1 1.35 3.47 0.18 10.7 17.4 2000 0.5 NoDADPVS 2 3.25 1.04 0.71 25.8 5.2 2000 4.0 No Notes: DADMAC (Floquat4540, SNF Inc., aqueous solution with 40% polymer actives), Poly(vinylsulfate), (Sigma Aldrich, sodium salt, aqueous solution with 25% polymeractives)

TABLE 4.2 Compositions of PECs Produced Via Dilution of PrecursorCompositions from Table 4.1 Total polymer Formulation PrecursorPrecursor NaCl, Water, DADMAC PVS, concentration, R NaCl NameComposition grams grams grams mM mM mM value pH mM Precipitate DADPVS 3DADPVS 1 0.13 2.00 97.88 0.83 1.67 2.5 0.5 2.0 100 Yes DADPVS 4 DADPVS 10.30 2.00 97.70 2.00 4.00 6.0 0.5 5.5 100 Yes DADPVS 5 DADPVS 2 0.752.00 97.25 12.0 3.00 15.0 4.0 6.75 100 No DADPVS 6 DADPVS 2 0.75 — 99.2512.0 3.00 15.0 4.0 6.80 0 No

Although Formulations DADPVS 3 and DADPVS 4 showed the presence ofprecipitate at an R value of 0.5, it is believed that the addition ofadditional NaCL or hypochlorite salt (e.g., NaOCl) electrolyte (e.g.,500 mM) would be sufficient to prevent precipitate formation.

TABLE 4.3 Z-average diameter and zeta potential of PECs Produced ViaDilution of Precursor Compositions from Table 4.2 Total PolymerZ-average Zeta Formulation R concentration, diameter, Potential, NameValue mM nm mV Comments DADPVS 5 4.0 15 66.33 +28.4 Diluted with watercontaining 100 mM NaCl as electrolyte DADPVS 6 4.0 15 61.64 +29.3Diluted with deionized water, precursor to water

The results in Table 4.3 show that stable PECs, at total polymerconcentrations of 15 mM (significantly higher than in examples 1-3) areproduced via dilution of the precursor solution with deionized water.The PECs produced exhibit a cationic (positive) zeta potential, asexpected, since R is significantly greater than 1.0.

The results in Table 4.3 also show that stable PECs may be produced viadilution of the precursor solutions with an aqueous diluent comprisingsignificant amounts of an electrolyte. Sodium chloride was used as asubstitute for sodium hypochlorite in Example 4, in order to ensuremeasurement of the zeta potential of the PECs produced via dilution wasnot compromised by the presence of the oxidant. It is believed, withoutbeing bound by theory, that the difference between the chloride andhypochlorite salts is immaterial to stability, both being electrolytes,in terms of their effects on the initial formation of the PECs via thedilution process. The results also show that the diameters of the PECsproduced via dilution in deionized water or water with electrolyte aresimilar, i.e, the rapid assembly of PECs during the dilution process,even with the presence of additional electrolytes, is readily achievedand does not require significant changes in the dilution process toaccommodate electrolytes or oxidants like hypochlorite in the dilutionliquid employed.

Example 5 Characterization of PECs Produced Via Dilution of PECPrecursor Solutions and Direct Assembly of PECs Under Dilute Conditions

Aqueous solutions comprising PECs produced via dilution from PECprecursor solutions were compared with aqueous solutions comprising PECsmade via the direct assembly method taught in US 201110236582. Some ofthe compositions also included NaCl as an electrolyte, and as asubstitute for sodium hypochlorite, for reasons described in Example 4.

The precursor solutions comprising DADMAC and PAA were prepared using aprocedure identical to the procedure described in Example 1. An aqueoussolution of DADMAC was weighed and dispensed into a glass beakerfollowed by the appropriate volume of an aqueous solution of succinicacid (5 wt %) and additional water. This solution was thoroughly mixedusing simple agitation. Finally, an aqueous solution of PAA (26% polymeractives) was weighed and added to the solution followed by mixing bysimple agitation. The resulting precursor solutions were viscous, clearto clear-blue liquids without insoluble macroscopic particles. Theultimate solutions of diluted PECs were prepared by dispensing theprecursor solution into an appropriate vessel, followed by introductionof a volume of water required to reach an ultimate total polymerconcentration of approximately 1.6 mM. Once the solution was thoroughlymixed by simple agitation, the pH was adjusted to the desired pH value.

TABLE 5.1A PECs Precursor Compositions used to prepare PECs via DilutionTotal polymer Formulation DADMAC, PAA, Succinic Water, DADMAC, PAA,concentration, Succinic R Name grams grams Acid, grams grams wt % wt %mM Acid, wt % value Precipitate DADPAA 9 5.20 7.00 61.47 26.40 2.06 1.83385 3.07 0.5 No DADPAA 10 12.52 2.11 61.42 23.99 4.96 0.55 385 3.07 4.0No Notes: DADMAC (Floquat 4540, SNF Inc., aqueous solution with 40%polymer actives), PAA (Aquatreat AR4, Akzo Nobel, aqueous solution with26% polymer actives), Succinic Acid (5 wt % aqueous solution)

TABLE 5.1B Compositions of PECs prepared via Dilution Total polymerFormulation Precursor Precursor, NaCl, Water, concentration, DADMAC,PAA, NaCl, Name sample grams grams grams mM mM mM mM pH DADPAA 11 DADPAA9 0.41 0 99.6 1.6 1.05 0.52 0 7.04 DADPAA 12 DADPAA 9 0.41 1.62 98.1 1.61.05 0.52 1.38 6.99 DADPAA 13 DADPAA 10 0.47 0 99.6 1.8 1.45 0.36 0 7.03DADPAA 14 DADPAA 10 0.45 1.62 98.3 1.7 1.38 0.35 1.32 7.01 Notes: NaCl(0.5 wt % aqueous solution)

Dilute PECs described by Tables 5.2A and 5.2B were prepared via thedirect assembly method using the following procedure. Stock C (succinicacid solution), Stock D (sodium chloride solution), and water were firstcombined. Second, the minor polymeric component was added to thesolution followed by the addition of the major polymeric component.After the solution was mixed by simple agitation, the pH was adjusted tothe desired pH value.

TABLE 5.2A Stock solutions Used for Direct Assembly of Dilute PECsFormulation R PAA Stock, DADMAC Stock C, Stock D, Water, Name Valuegrams Stock, grams grams grams grams DADPAA 15 0.5 10.0 5.0 2.4 0 82.6DADPAA 16 0.5 10.0 5.0 2.4 1.6 81.1 DADPAA 17 4.0 3.0 12.0 2.4 0 82.6DADPAA 18 4.0 3.0 12.0 2.4 1.6 81.1 Notes: PAA Stock: Aquatreat AR4,Akzo Nobel, aqueous solution with 0.071% polymer actives. DADMAC Stock:Floquat 4540, SNF Inc., aqueous solution with 0.161% polymer actives.Stock C: Succinic Acid; 0.50 wt % aqueous solution. Stock D: SodiumChloride; 0.50 wt % aqueous solution

TABLE 5.2B Final Compositions of Solutions with Direct Assembly of PECsTotal polymer Formulation DADMAC, PAA, concentration, Succinic NaCl, RName mM mM mM Acid, mM mM pH value DADPAA 15 0.50 1.00 1.5 1.0 0 6.990.5 DADPAA 16 0.50 1.00 1.5 1.0 1.3 7.07 0.5 DADPAA 17 1.20 0.30 1.5 1.00 7.03 4.0 DADPAA 18 1.20 0.30 1.5 1.0 1.3 7.01 4.0

TABLE 5.3 Z average diameters and Zeta Potential of PECs Produced ViaDilution from Precursor Solutions or from a Direct Assembly Method TotalPolymer Z-average Zeta Formulation R concentration, diameter, Potential,Name Value mM nm mV Comments DADPAA 11 0.5 1.5 392.9 −54.2 No NaClDADPAA 12 0.5 1.5 104.7 −47.2 NaCl DADPAA 13 4.0 1.5 200.6 +29.4 No NaClDADPAA 14 4.0 1.5 184.2 +31.5 NaCl DADPAA 15 0.5 1.5 244.4 −51.5 No NaClDADPAA 16 0.5 1.5 245.8 −52.0 NaCl DADPAA 17 4.0 1.5 369.7 +32.4 No NaClDADPAA 18 4.0 1.5 371.5 +34.9 NaCl Notes - Z-average diameters are meansof triplicate analyses. Zeta potentials are means of duplicate analyses.

The results in Table 5.3 show that stable PECs may be produced viadilution of PEC precursor solutions at R values both below and aboveR=1.0. Since the pH of the diluted aqueous solutions was adjusted to benear neutral, (near pH 7), the PECs produced via the dilution methodwith R values less than 1.0 (DADPAA 5 and 6) exhibit anionic (negative)zeta potential values due to the excess of anionic groups provided bythe ionized carboxylate groups of the PAA comprising the PECs.Alternatively, PECs with cationic (positive) zeta potential values maybe produced via dilution of the PECs precursor solutions formulated at Rvalues greater than 1.0 (DADPAA 7 and 8). All PECs produced via thedilution of precursor solutions exhibit Z-average diameters that aresmall enough (less than 500 nm) to ensure colloidal stability. The PECswere produced via dilution in either the absence or presence ofelectrolyte, indicating, as discussed elsewhere, that the assembly ofPECs occurs rapidly during the dilution, and does not require anyspecial changes in the dilution process when electrolyte (or an oxidantsuch as hypochlorite, which will behave similarly) is present.

The results in Table 5.3 also show that stable PECs produced via thedirect assembly method also exhibit Z-average diameters small enough toensure colloidal stability, and also zeta potential values which can becontrolled via the R parameter.

The results in Table 5.3 also show that the mean zeta potential valuesof the PECs produced via the method of the instant invention, at a givenR value with the same electrolyte concentration, are very similar to thezeta potential values of the PECs made via the direct assembly method.According to the manufacturer of the instrument used to determine thezeta potentials cited herein, the expected variation in zeta potentialof a given sample should be about 10% relative.

The inventors believe, based on the trends in the results in Table 5.3,that the PECs produced via the dilution method of the instant inventionare qualitatively similar to those produced via the direct assemblymethod. Thus, the present invention provides an important, new versatileapproach to the use, production, and delivery of PECs of controlled sizeand charge.

Example 6—Compositions and Characterization of PECs Prepared ViaDilution of Precursor Solutions with Aqueous Solutions of Surfactants

Aqueous solutions of PECs that also comprise surfactants of varioustypes may be prepared via dilution of PECs precursor solutions withaqueous solutions of surfactants to deliver aqueous cleaning solutionssuitable for hard surface cleaning. PEC precursor solutions may compriseone part, and a suitable aqueous solution of a surfactant may comprise asecond part of a two part system in which the two parts are combined viaa device that draws liquid from each of the separate parts into a streamof flowing water, producing a ready to use diluted aqueous formulationcomprising PECs and surfactants. Such ready to use solutions may beuseful in janitorial cleaning of floors and other hard surfaces, orcould be directed to other parts of a liquid control system for themanipulation of the charge of bacterial or fungal spores or virusparticles, or in the production of treated articles, including movingwebs of nonwovens, paper, fibers, etc. PEC precursor solutions may alsobe diluted with aqueous solutions comprising surfactants and optionally,adjuvants such as buffers, via a package comprising a trigger sprayercapable of drawing liquids from two separate chambers of a dual-chamberbottle, to deliver a diluted solution in a ready to use, portableformat.

The presence of surfactants in the final diluted solutions comprisingPECs may be desirable in order to further reduce the surface tension(air-water tension) of the aqueous solutions to facilitate wetting orcleaning rates, while also providing PECs of controlled size and chargefor the modification of substrate surfaces via the adsorption of PECs.

The compositions of PECs prepared by dilution with aqueous solutionscomprising surfactants were prepared by one of two methods. Either thePECs precursors were diluted into water or buffer solution to formdilute PECs first, followed by the addition of surfactant at the desiredconcentration (e.g. DPQ 1 in Table 6.1), or PECs precursors were dilutedinto a solution containing the surfactant (e.g. DPQ2, DPSLS1, DPAO1,DPAO2 in Table 6.1).

TABLE 6.1 PEC Solutions Prepared by Dilution with Aqueous SolutionsComprising Surfactants Total polymer pH of Pre- concen- Succinic Surfac-Surfac- Surfac- Surfac- Surfac- Surfac- final Formulation Precursorcursor, Water, tration, R Acid, tant 1, tant 1, tant 2, tant 2, tant 3,tant 3, solu- Name sample grams grams mM value mM grams wt % grams wt %grams wt % tion DPQ 1 DADPAA 10 0.19 49.8 1.5 4.0 1.0 0.18 0.02 — — — —7.04 DPQ 2 DADPAA 10 0.19 49.6 1.5 4.0 1.0 0.20 0.02 — — — — 6.55 DPSLS1 DADPAA 9 0.19 49.8 1.5 0.5 1.0 — — 0.18 0.02 — — 6.42 DPAO 1 DADPAA 90.19 49.6 1.5 0.5 1.0 — — — — 0.20 0.02 6.88 DPAO 2 DADPAA 10 0.19 49.61.5 4.0 1.0 — — — — 0.20 0.02 6.63 DADPAA 19 DADPAA 9 0.19 49.8 1.5 0.51.0 — — — — — — 6.94 DADPAA 20 DADPAA 10 0.19 49.8 1.5 4.0 1.0 — — — — —— 7.10 Notes: Surfactant 1: Quaternary ammonium surfactant; BTC 1010,Stepan Corp.; 5.0 wt % aqueous solution. Surfactant 2: Sodium laurylsulfate surfactant; SLS Crude, Stepan Corp.; 5.0 wt % aqueous solution.Surfactant 3: Amine oxide surfactant; Ammonyx LO, Stepan Corp.; 5.0 wt %aqueous solution

TABLE 6.2 Characterization of PEC Solutions Prepared by Dilution withAqueous Solutions Comprising Surfactants Total Polymer Z-average ZetaFormulation R concentration, diameter, Potential, Name Value mM nm mVComments DPQ 1 4 1.5 159.4 +32.2 Quat into PECs DPQ 2 4 1.5 170.6 +32.4PECs into quat DPSLS 1 0.5 1.5 164.5 −62.7 PECs into SLS DPAO 1 0.5 1.5135.1 −52.6 PECs into LO DPAO 2 4.0 1.5 197.4 +28.1 PECs into LO DADPAA19 0.5 1.5 363.0 −52.7 No surf control DADPAA 20 4.0 1.5 160.1 +25.3 Nosurf control

The results in Table 6.2 show that PECs with Z-average diameters lessthan 500 nm may be produced from dilution of PEC precursor solutionswith aqueous solutions that comprise surfactants and adjuvants designedto deliver a desired pH in the diluted solutions.

The target pH of the diluted solutions was near neutral (pH 6-7) toslightly acidic, and the PECs comprise DADMAC as the cationicpolyelectrolyte and PAA as the anionic polyelectrolyte. Thus, thecarboxylic acid groups of PAA will be in the fully ionized, anionicform, i.e., the pH of the diluted solutions is significantly higher thanthe estimated pKa of the carboxylic acid groups, or about 4. PECprecursor solutions formulated with R values >1.0 produce PECs withcationic (positive) zeta potential values upon dilution with aqueoussystems that do not comprise surfactants, as discussed herein.

The results for formulations DPQ1 and DPQ2 in Table 6.2 show that PECswith cationic zeta potential values are produced upon dilution withaqueous systems comprising cationic surfactants, in this case, cationicgermicides. In addition, the PECs produced by dilution of the precursorsolutions with aqueous systems comprising surfactants are very similarin size and zeta potential, and are not significantly affected by themanner of dilution. Sample DPQ1 was diluted by adding an aqueous quatsolution to the PECs precursor solution, while sample DPQ2 was made byadding the PECs precursor solution to an aqueous quat solution.Inventors believe, without being bound by theory, that the resultsindicate that because the PECs being produced and the aqueous micellesof the surfactant being produced upon dilution are of the same netcharge (cationic), there is electrostatic repulsion between the PECs andthe micelles, which minimizes or eliminates interactions between them,and hence PECs will rapidly assemble upon dilution of PEC precursorsolutions.

The results in Table 6.2 (sample DPSLS1) also indicate that PECprecursor solutions formulated at R values <1.0 (here at R=0.5), inorder to deliver PECs with anionic (negative) zeta potential values, maybe diluted with aqueous solutions comprising anionic surfactants. Thus,for the reasons discussed above, stable PECs of suitable Z-averagediameter and anionic charge are observed in the final dilution of sampleDPSLS1.

When the aqueous solution used for dilution of a PEC precursor solutioncomprises a nonionic surfactant or an amphoteric surfactant such as anamine oxide in an aqueous solution with a pH adjusted such that thesurfactant exhibits no charge (in this case an amine oxide near pH 7),little electrostatic interaction between the surfactant molecules ormicelles and the PECs would be expected. The results in Table 6.2 show(samples DPAO1 and DPAO2) that PEC precursor solutions deliver stablePECs of appropriate Z-average diameter when they are diluted with anaqueous solution comprising an uncharged amine oxide (nonionicsurfactant). The results also show that the net charge on the PECsproduced via dilution can be controlled via the R parameter of theprecursor solution, i.e, PECs with anionic charge (negative zetapotential) are produced with R values <1.0 and PECs with cationic charge(positive zeta potential) are produced with R values >1.0.

Example 7—Compositions and Characterization of PECs Prepared ViaDilution of Precursor Solutions with Aqueous Solutions of Germicides

Aqueous solutions comprising stable PECs produced via the presentinvention may be used to modify the properties of both hard surfaces(glass, tile, porcelain, metals and the like) as well as soft surfaceslike fabrics, nonwoven or woven, paper, or fibers of any type, throughthe rapid adsorption of PECs onto such surfaces. It is also possible toprovide extended antimicrobial properties to such surfaces through theadsorption of PECs that comprise an antimicrobial agent such as agermicidal quat, a non-polymeric biguanide such as chlorhexidine oralexidine, or a metal ion such as silver, copper and the like.

Inventors believe, without being bound by theory, that stable PECscomprising such antimicrobial agents are able to anchor theantimicrobial agents to said surfaces. Thus, in a single step process,the surface is exposed to an aqueous solution comprising PECs. Theantimicrobial agent not only provides disinfection during the exposure,but also imparts extended or residual antimicrobial properties to thesurface. Alternatively, said surfaces may be treated in a two-stepprocess comprising exposing the surface to an aqueous solution of stablePECs, followed by exposure to a second aqueous solution comprising theantimicrobial active, whereby the active becomes anchored to the PEClayer established on the surface during the first exposure.

TABLE 7.1 Compositions of PEC Precursor Solutions for Dilution withAqueous Solutions Comprising Surfactants BTC Total 1010 polymer pH ofPre- BTC stock concen- Succinic BTC final Formulation Precursor cursor,Water, 1010, concen- NaOH, tration, R Acid, 1010, solu- Precip- Namesample grams grams grams tration grams mM value mM wt % tion itateComments - DPQ 3 DADPAA 9 0.19 49.6 0.20  5 wt % 2.6 1.5 0.5 1.0 0.026.03 No NaOH added to quat solution, no pH adjustment, PECs into quatDPQ 4 DADPAA 9 0.39 96.33 1.00 40 wt % 2.5 1.5 0.5 1.0 0.4 5.21 NoHigher quat level, NaOH added to quat solution DPQ 5 DADPAA 9 0.41 96.151.01 40 wt % 3.0 1.5 0.5 1.0 0.4 7.18 No Quat into PECs, pH adjustedNotes: NaOH (0.4 wt % aqueous solution)

TABLE 7.2 Characterization of PECs Made Via Dilution of Precursors TotalPolymer Z-average Zeta Formulation R concentration, diameter, Potential,Name value mM nm mV Comments DPQ3 0.5 1.5 142.6 +37.8 PECs into quatsoln, 0.02% BTC1010 DPQ4 0.5 1.5 191.5 +56.9 PECs into quat 0.4% BTC1010DPQ5 0.5 1.5 376.1 +51.8 Quat into PECs - 0.4% BTC1010

The results in Table 7.2 show that stable PECs may be produced bydilution of a PECs precursor solution with an aqueous solutioncomprising a surfactant. The PEC precursor solution was formulated withthe R value <1.0, in order to produce PECs with an anionic charge whichwould have a strong electrostatic interaction with the cationicsurfactant, here a germicidal quat, present in the aqueous solution usedto dilute the PECs precursor solution. Thus, the zeta potentials of thestable PECs produced via dilution are cationic (positive), that is,“charge reversed” relative to the R parameter of the precursor solution.Inventors believe, without being bound by theory, that the stable PECsproduced are “decorated” with quat molecules through interactions of thecationic headgroups of the quats and the ionized carboxylate groups ofthe PAA comprising the PEC.

Thus, stable PECs may be produced via dilution of the precursorsolutions of the instant invention, even if the aqueous diluent solutioncomprises a surfactant of opposite charge to the net charge of the PECswhich would be produced in the absence of the surfactant, where saidcharge of the PECs can be controlled by adjusting the R parameter. Asshown in the examples, the concentration of the quat in the finaldiluted aqueous solution may be adjusted, depending on the antimicrobialand surface modification performance and kinetics desired.

This example also illustrates another method for controlling the zetapotential of the PECs of the instant invention, i.e. through“decoration” with soluble surfactants of net opposite charge to thePECs. The PECs are rapidly assembled during the dilution step with sizesappropriate for colloidal stability (<500 nm Z-average diameter) in asingle step, eliminating any need for isolation and further mechanicalmanipulation, for example through high shear mixing, allowing for thedirect use of the dilute final solution comprising the decorated PECsfor treatment of a surface to modify its properties.

Example 8—Compositions and Characterization of PECs Prepared ViaDilution of Precursor Solutions with Aqueous Solutions of Surfactants inMultiple Steps

Stable PECs may be produced via dilution of PEC precursor solutions ofthe instant invention, even when the diluent used comprises surfactants,and even if the relative charges of the surfactant in the diluentsolution and the PECs produced via manipulation of the R parameter areopposites. Thus, “decorated” and “charge-reversed” PECs, which can beuseful for controlling the modification of surfaces, and for anchoringantimicrobial compounds such as quats and biguanides onto surfaces toprovide extended antimicrobial properties may be produced.

Decorated or charge-reversed PECs may also be produced in multiple stepprocesses. Thus, a PEC precursor composition shown in Table 8.1 wasdesigned to yield PECs with a net anionic charge upon dilution with anaqueous solution comprising an amine oxide surfactant. In this example,stable PECs were produced by adding an amine oxide solution to theprecursor solution, with simple agitation provided by a magneticstirbar. The characteristics of the PECs produced via this firstdilution are shown in Table 8.2.

A subsample (9 ml) of formulation DPAO3 was added to a vial with amagnetic stirbar. To this subsample, 1 ml of an aqueous solution ofBTC1010 (0.2%) was added with stirring, to produce a clear solution freeof coacervates and precipitates containing the PECs and the germicidalquat at 0.02%. The characteristics of the PECs in this final dilutesolution (sample DPAOQ1) are also shown in Table 8.2.

TABLE 8.1 Composition of PEC Precursor Solution For Dilution WithAqueous Solutions Comprising Surfactants in Two Steps Ammonyx Totalpolymer Formulation Precursor Precursor, Water, Ammonyx LO stockconcentration, R Succinic Ammonyx Precip- Name sample grams grams LO,grams concentration mM value Acid, mM LO, wt % itate DPAO3 DADPAA 9 0.1331.05 2.2 0.3 wt % 1.5 0.5 1.0 0.02 No

TABLE 8.2 Characterization of PECs Produced Via Dilution of PECsPrecursor Solutions Total Polymer Z-average Zeta Formulation Rconcentration, diameter, Potential, Name Value mM nm mV Comments DPAO30.5 1.5 209.7 −45.8 LO into PECs - no salt, original dilution DPAOQ1 0.51.35 211.4 +36.1 0.2% BTC1010 added to above

The results in Table 8.2 show that stable PECs of appropriate size andwith a net anionic charge (negative zeta potential) can be produced viadilution of PECs precursor solution with an aqueous solution comprisingan amine oxide at pH near neutral. The rapid assembly of the PECs viathe dilution of appropriate precursor solutions prevents the formationof precipitates or coacervates due to interactions between thesurfactant micelles and the PECs during the assembly process.

The results in Table 8.2 also show that stable PECs of net anioniccharge (negative zeta potential) may be further diluted with asurfactant solution comprising a cationic surfactant, here a germicidalquat, in order to produce stable PECs that are decorated with the quatmolecules via electrostatic interactions. These interactions result inthe reversal of charge of the PECs, allowing PECs produced fromprecursor solutions formulated at R=0.5 to exhibit a cationic zetapotential. Such decorated PECs are useful in the subsequent modificationof surfaces, since germicidal quats may be anchored onto surfaces inthis manner.

Example 9—Compositions and Characterization of PECs Prepared ViaDilution of Precursor Solutions with Alkaline Sodium Hypochlorite

The PEC precursor solutions may comprise a concentrated solution ofsodium hypochlorite (8.25%, for example), which is added to laundry bythe household consumer via direct addition to the wash water, or throughthe use of an automated dosing reservoir for the hypochlorite bleachthat is provided by many washing machine manufacturers. A typical doserate of bleach in a home washing is about ½ cup for a top-loading washercontaining 69 liters of water. Thus, the PEC precursor solutions withhypochlorite are designed to produce PECs in the wash water when dilutedby a factor of about 583 (583:1).

Table 9.1 summarizes the compositions of PEC precursor compositions withsodium hypochlorite which can deliver PECs of various R values whendiluted in water by a factor of 583.

TABLE 9.1 PEC Precursor Compositions Comprising Concentrated SodiumHypochlorite (and Controls) Total polymer concen- Formulation DADMAC,PAA, NaOCl, NaOH, NaCl, Water, DADMAC, PAA, tration, R Precip- Namegrams grams grams grams grams grams wt % wt % mM pH value itate CommentsDADPAA 21 0.50 1.45 38.16 — — 7.33 0.42 0.74 130 12.64 0.25 No DADPAA 227.85 10.72 343.48 — — 72.49 0.70 0.62 130 12.64 0.50 No DADPAA 23 1.101.03 38.17 — — 8.27 0.90 0.53 130 12.55 0.75 No DADPAA 24 12.62 6.80343.46 — — 76.16 1.20 0.40 130 12.64 1.33 No DADPAA 25 1.72 0.61 38.19 —— 8.64 1.40 0.31 130 12.59 2.0 No DADPAA 26 18.97 3.29 343.45 — — 79.731.67 0.19 130 12.67 4.0 No DADPAA 27 0.85 1.19 — 3.23 6.49 37.00 0.700.62 130 12.48 0.50 No no hypo control DADPAA 28 2.11 0.37 — 2.01 6.5036.03 1.67 0.19 130 12.45 4.0 No no hypo control PAA 1 — 1.78 38.18 2.60— 7.47 — 0.92 130 12.52 — No PAA only control DADMAC 1 2.01 — 38.18 — —9.20 2.09 — 130 12.69 — No DADMAC only control Notes: DADMAC (Floquat4540, SNF Inc., aqueous solution with 40% polymer actives), PAA(Aquatreat AR4, Akzo Nobel, aqueous solution with 26% polymer actives),NaOCl (aqueous solution containing 10.8 wt % sodium hypochlorite and 8.5wt % sodium chloride), NaOH (1.0M aqueous solution), NaCl (solidgranules, 100% actives).

Table 9.2 summarizes the characterization of the diameters and the zetapotentials of the PECs produced from the precursor solutions describedabove. The samples were prepared by adding 30.9 microliters (viaadjustable pipet) to 18.0 milliliters of water contained in a 20 mlcapped vial. The solutions were gently mixed by brief shaking of thecapped vial, and then a 1 ml sample was removed and loaded into either adisposable scattering cuvette or into the disposable zeta potential cellused with the Malvern Zetasizer. The water used for dilution was eitherdeionized or was synthetic hard water containing 100 ppm total hardnessions. Due to the significant dilution of the precursor solutions of thisexample, it is believed that the mean zeta potentials of the PECs formedby dilution may be measured in the presence of the sodium hypochlorite.

TABLE 9.2 Compositions and Characterization of PECs Produced ViaDilution of Precursor Compositions from Table 9.1 Total polymerZ-average Zeta Formulation Precursor Precursor, Water, Hard DADMAC, PAA,concentration, R diameter, potential, Name Composition μL mL water, mLmM mM mM value nm mV DADPAA 29 DADPAA 21 30.9 18.0 — 0.3 1.2 1.5 0.25170.7 Not measured DADPAA 30 DADPAA 21 30.9 — 18.0 0.3 1.2 1.5 0.25204.6 Not measured DADPAA 31 DADPAA 22 30.9 18.0 — 0.5 1.0 1.5 0.50218.0 −45.9 DADPAA 32 DADPAA 22 30.9 — 18.0 0.5 1.0 1.5 0.50 640.6 −9.58 DADPAA 33 DADPAA 23 30.9 18.0 — 0.64 0.86 1.5 0.75 269.0 Notmeasured DADPAA 34 DADPAA 23 30.9 — 18.0 0.64 0.86 1.5 0.75 551.3 Notmeasured DADPAA 35 DADPAA 24 30.9 18.0 — 0.86 0.64 1.5 1.33 222.2 +55.2DADPAA 36 DADPAA 24 30.9 — 18.0 0.86 0.64 1.5 1.33 207.6 +49.8 DADPAA 37DADPAA 25 30.9 18.0 — 1.0 0.5 1.5 2.0 182.8 +51.0 DADPAA 38 DADPAA 2530.9 — 18.0 1.0 0.5 1.5 2.0 224.9 +48.2 DADPAA 39 DADPAA 26 30.9 18.0 —1.2 0.3 1.5 4.0 192.9 +56.7 DADPAA 40 DADPAA 26 30.9 — 18.0 1.2 0.3 1.54.0 218.9 +46.8 DADPAA 41 DADPAA 27 30.9 — 18.0 0.5 1.0 1.5 0.5 551.8Not measured DADPAA 42 DADPAA 28 30.9 — 18.0 1.2 0.3 1.5 4.0 323.9 Notmeasured PAA 2 PAA 1 30.9 — 18.0 — 1.5 1.5 — Too dilute to measureDADMAC 2 DADMAC 1 30.9 — 18.0 1.5 — 1.5 — Too dilute to measure PAA1 — —— — — 130 130 — 32.3 Not measured DADMAC1 — — — — 130 130 — 19.2 Notmeasured Notes: Synthetic hard water contained 100 ppm hardness asCa⁺²/Mg⁺² in mole ratio of 3:1.

The results in Table 9.2 indicate that stable PECs are formed bydilution in deionized water of the PEC precursor solutions comprisingsodium hypochlorite over a wide range of R values, i.e, from 0.25 to4.0. The results also indicate that the PECs formed by dilution indeionized water exhibit negative mean zeta potentials when the R valueof the precursor solution is less than 1, and exhibit positive mean zetapotentials when the R value of the precursor solutions are greater than1, which is expected for this example since the pH of the precursorsolutions is high (designed to be greater than 12.0), which ensures fullionization of the carboxylic acid groups of the poly(acrylic acid)incorporated into the PECs. As discussed herein, control of the zetapotential of PECs comprising poly(acrylic acid) and like polymers madevia dilution from precursor solutions is possible through variation ofthe pH of the precursor solution and/or the pH of the final dilutedsolution comprising the PECs.

The results in Table 9.2 also indicate that stable PECs are formed bydilution in hard water of the PECs precursor solutions comprising sodiumhypochlorite at R values of less than 0.5, and also at R values greaterthan 1.0. At R=0.50 and R=0.75 of the precursor solutions, the diametersof the PECs formed by dilution in hard water are significantly largerthan in the case of dilution in deionized water (see examples DADPAA 32and DADPAA 34). Inventors believe, without being bound by theory, thatbinding of significant amounts of divalent ions present in the hardwater (for example, Ca⁺² and Mg⁺² ions) to the PECs formed by dilutionof the precursors can occur. Evidence for this binding includes thecationic (positive) shift in the zeta potential of the PECs formed bydilution of the precursor solution with R=0.5 in deionized water (meanzeta=−45.9) to a value of −9.58 in hard water.

The results in Table 9.2 also show that stable PECs of suitably smalldiameter can be formed by dilution of PECs precursor solutions in hardwater when the R values of the precursor solutions comprisinghypochlorite are >1.0.

The results in Table 9.2 also show that stable PECs are formed bydilution in hard water of PECs precursor solutions in which sodiumchloride has been substituted for the sodium hypochlorite on a molarbasis. Thus, Examples DADPAA41 and DADPAA42 show that PECs are formed bydilution of precursor solutions comprising high electrolyte levels (2.2M NaCl). As discussed herein, incorporation of electrolytes in theprecursor solutions can be helpful, and can be adjusted to provideclear, stable precursor solutions which can deliver PECs of controlledsize and charge upon dilution.

Analysis of two control formulations (PAA2 and DADMAC2) comprisinghypochlorite and a single polymer was not possible when the formulationswere diluted in the same manner as the PEC precursor solutions, due tothe very low level of light scattering by the soluble polymer chains insolution. Those skilled in the art will recognize this limitation asbeing due to the much smaller overall size of the soluble polymer chainswhen they are not incorporated into PECs, and to the fact that theabsolute levels of light scattering in DLS experiments will scale withthe diameter of the scattering particles to the sixth power, i.e.,scattering is proportional to (diameter)⁶. Thus, the neat controlformulations PAA1 and DADMAC1 were instead analyzed. The increasedconcentration of the polymers in these formulations (130 mM) yieldedenough light scattering for the determination of the average diametersof the soluble polymer chains, which were confirmed to be much smallerthan that of the PECs made by dilution of the precursor solutions, asexpected.

TABLE 9.3 Hypochlorite Concentration in PEC Solutions from Table 9.1Remaining in Solution when Incubated at 49° C. Total polymerHypochlorite Concentration in concen- Solution Incubated at 49° C., wt %Formulation tration, R Initial Day Day Day Day Name mM value value 7 1421 28 DADPAA 26 130 4.00 8.1 4.9 3.5 0.4 0.0 DADPAA 25 130 2.00 8.3 5.23.6 2.7 2.1 DADPAA 24 130 1.33 8.4 5.2 3.7 2.0 2.1 DADPAA 23 130 0.758.2 5.1 3.7 2.8 2.4 DADPAA 22 130 0.50 8.1 5.1 3.6 2.3 2.5 DADPAA 21 1300.25 8.2 5.2 3.7 2.8 2.3 PAA 1 130 — 8.2 5.2 3.8 2.9 2.3 DADMAC 1 130 —8.5 5.1 0.3 0.0 0.0

Spores (or more properly, endospores) are a type of dormant cellproduced by many types of bacteria, such as Bacillus and Clostridium, inresponse to stressful environmental conditions. The exterior coats ofspores, which are responsible for the resistance to extreme conditions,are multi-layer structures composed primarily of cross-linkedpolypeptides. When a spore encounters an environment favorable forgrowth of vegetative cells, the spore coat allows passage of nutrientsand water to the spore, and the production of a vegetative cell, in agermination process.

The compositions of the polypeptides, proteins, and other minormaterials that make up the coat of Bacillus subtilis spores, forexample, result in the spore exhibiting a net anionic charge (negativezeta potential) when the spores are dispersed in water at neutral pH,i.e., pH 7. Polypeptides in aqueous solutions will exhibit a net chargeas a function of pH of the solution that is determined by the relativenumbers of anionically and cationically charged amino acids in thepolypeptide chain. At a pH corresponding to the isoelectric point of apolypeptide, the net charge on the polypeptide is zero, due to thepresence of equal numbers of cationically charged and anionicallycharged amino acids. The net charge on the polypeptide at pH valuesgreater than the isoelectric point will thus be negative (anionic), andwill be positive (cationic) at pH values below the isoelectric point.The isoelectric points (or point of zero charge) of various Bacillusspores have been found to lie between about pH 3 and pH 4. Thus, thezeta potential of the spores used herein was found to be cationic(positive) when the spores were dispersed in water adjusted to around pH2, i.e., well below the known isoelectric point.

Bacillus spores exhibit average diameters of around 1000 nm (1micrometer), and can thus act as charged scattering particles whendispersed in aqueous media. Measurements of the zeta potential of sporesare thus readily accomplished using the approach of laser Dopplervelocity determination that is implemented in modern instruments, suchas the Malvern Zetasizer. Those skilled in the art will realize that anappropriate concentration of spores for such measurements of the zetapotential of the spores can readily be determined, using dilutions ofstandard dispersions of spores which are commercially available.Typically, the spore concentrations in these standard dispersions areexpressed as spores/ml or colony forming units/ml of the dispersions.Inventors have found that reproducible measurements of the zetapotential of Bacillus spores can easily be made at spore concentrationsof around 1 to 3.3×10⁶ spores/ml. Such concentrations are readily madeby dilution of commercially available stocks with concentrations of1×10⁸ spores/ml.

Spores contaminating surfaces such as towels or laundry or hard surfacessuch as floors, walls, medical equipment, food preparation or servicecounters, etc. will germinate and grow, producing increasing numbers oforganisms on the surface, when the environment becomes favorable, forexample, when the surface becomes soiled or contaminated with materialsthat are suitable nutrients for the microorganisms. Germicidalquaternary ammonium compounds or biguanides or certain cationicpolymers, such as chitosan, have little effect on dormant spores, but ifthey are present on the surface of the spores in sufficientconcentration, they can kill the organism at the initial stage ofgermination when the environmental conditions become favorable.

During the cleaning of surfaces potentially contaminated with spores,especially in healthcare facilities, it is critical that spores areefficiently removed by the rag, mop, wipe cloths or other cleaningimplements used to contact the cleaning solution with the surfaces. Thesurface charge on the majority of cleaning implements is negative(anionic) zeta potential, and hence have a tendency to electrostaticallyrepel any spores, which also have a native negative (anionic) zetapotential. Cleaning solutions comprising PECs, which will rapid adsorbonto the surfaces of the spores and thus increase the zeta potential topositive (cationic) values can aid in the efficiency of the mechanicalremoval of the spores from the surfaces and aid in the retention of thespores on or in the cleaning implement, thus preventing mechanicalre-spreading of the spores to other surfaces.

In some applications, such as the use of spores as bio-insecticides,bio-fungicides, or bio-control agents, as foliar sprays or seedcoatings, the increased adhesion of spores to the surfaces of seeds orcrops should be combined with low spore toxicity, in order to ensure anet increase in efficiency of the process. Thus, the polyelectrolytesselected for assembly into the PECs, and especially the cationicpolyelectrolyte, must show little or no toxicity to the vegetative formof the cells resulting from the germination of the spores, and must showlittle or no tendency to inhibit the germination rates of the sporesupon use in the field.

Example 10—Modification of the Zeta Potential of Bacillus Spores ViaInteractions with PECs Produced by the Dilution of PECs PrecursorSolutions

In order to demonstrate the utility of PECs for the modification of thesurface charge of microorganisms, the zeta potentials of Bacillussubtilis spores dispersed in aqueous solutions of PECs produced fromdilution of PEC precursor solutions were measured.

Dispersions of the spores in water or in aqueous solutions comprisingPECs at spore concentrations of at least 1×10⁶ were all prepared in thesame manner. Ten microliters of a fresh commercially availabledispersion of Bacillus subtilis spores (spore concentration of 1×10⁸spores/ml) were added to 990 microliters of water or aqueous solutioncomprising PECs, gently mixed by drawing into and expelling from amanually operated pipette with a disposable tip, followed by loading ofthe entire sample into a disposable capillary zeta potential measurementcell.

PEC precursor solutions with values of the R parameter both less thanand greater than 1.0, which were clear and free of coacervates andprecipitates were prepared with compositions summarized in Table 10.1.The precursor solutions were then diluted in a first step to provideaqueous solutions comprising PECs of both net anionic charge (Rparameter <1) and net cationic charge (R parameter >1) all at the sametotal polymer concentration of 1.5 mM.

In order to demonstrate the effect of the concentration of PECs made inthis manner on the zeta potential of Bacillus spores, serial dilutionsof the samples of PECs made at 1.5 mM were also made with deionizedwater.

TABLE 10.1 Compositions of PEC Precursor Formulations Used to DeliverAqueous Solutions of PECs for the Modification of the Surfaces ofBacillus Spores Total polymer Formulation Precursor Precursor, Water,concentration, DADMAC, PAA, R Name sample grams grams mM mM mM value pHPDS1 DADPAA 9 0.41 99.6 1.6 1.05 0.52 0.5 7.04 PDS2 DADPAA 10 0.47 99.61.8 1.45 0.36 4.0 7.03 Notes: DADMAC (Floquat 4540, SNF Inc., aqueoussolution with 40% polymer actives), PAA (Aquatreat AR4, Akzo Nobel,aqueous solution with 26% polymer actives),

TABLE 10.2 Characterization of Bacillus Subtilis Spore DispersionsContaining at Least 1 × 10⁶ spores/ml in Absence and Presence of PECsPrepared from Precursor Solutions Total Polymer Zeta Formulation Rconcentration, Potential of Name value mM Spore, mV Comments Control 1 —— −27.4 Spores only dispersed in water, pH 7 Control 2 — — +12.4 Sporesonly dispersed in 0.01N HCl, pH 2 PDS1 0.5 1.5 −51.5 Spores with PECsproduced from dilution of precursor solution PDS1A 0.5 0.15 −44.8 Sporeswith PECs serially diluted from PDS1 PDS1B 0.5 0.015 −42.0 Spores withPECs serially diluted from PDS1 PDS1C 0.5 0.0015 −47.3 Spores with PECsserially diluted from PDS1 PDS2 4.0 1.5 +31.6 Spores with PECs producedfrom dilution of precursor solution PDS2A 4.0 0.15 +27.0 Spores withPECs serially diluted from PDS2 PDS2B 4.0 0.015 +15.3 Spores with PECsserially diluted from PDS2 PDS2C 4.0 0.0015 +7.03 Spores with PECsserially dilUted from PDS2 PDS2D 4.0 0.0015 +6.45 Spores with PECsserially diluted from PDS2 Notes - zeta potential values are averages ofat least 2 replicate measurements. The precision of replicatemeasurements is estimated as 10% relative or better by the instrumentmanufacturer.

The results in Table 10.2 (Control 1) indicate that the zeta potentialof the spores dispersed in water at neutral pH is found to be negative(anionic charge), which is expected. The anionic charge on the spores atneutral pH is thought to be due primarily to the composition of thepolypeptides, proteins, and other minor components of the spore coat.The isoelectric points (or point of zero charge) of various Bacillusspores are known to lie between about pH 3 and pH 4. Thus, the zetapotential of the spores used herein was found to be cationic (positive),when the spores were dispersed in water adjusted to around pH 2 (Control2), i.e., well below the known isoelectric point.

The results in Table 10.2 show that the zeta potential of the spores canbe adjusted by exposing the spores to aqueous solutions comprising PECsmade via dilution of precursor solutions. The PECs made via dilution ofPDS1, formulated with an R value of 0.5 will exhibit a net negative zetapotential, but are capable of adsorbing, and hence modifying, surfacessuch as silica that also exhibit a net negative charge at a given pH.Inventors believe, without being bound by theory, that the stable PECsof the instant invention have enough cationic charges (here due to theDADAMC of the PECs) readily available to the anionic sites on solidsurfaces to drive adsorption of the PECs onto the solid surfaces.Alternatively they may be sufficiently flexible or capable of structuralchanges at solid surfaces such that adsorption of the PECs, whichexhibit a net negative (anionic) zeta potential, readily occurs onsurfaces which also have a net negative charge, such as silica at pH7.0.

Thus, the zeta potential of the spores exposed to PECs made at R=0.5(formulation PDS1) is significantly more anionic (more negative) thanthat of the control spores, due to the adsorption of PECs onto the sporesurfaces. Inventors believe, without being bound by theory, that thecationic sites of the PECs are readily available for electrostaticinteractions with the negative sites on the spore coat surface, andhence the PECs are rapidly adsorbed onto the spores. A reduction in thenumber of anionic sites on the spore surface (at neutral pH, i.e., wellabove the isoelectric point of the spore) through “neutralization” byadsorption of a cationic species, such as a cationic germicidesurfactant, would be expected to shift the zeta potential of the sporein a positive direction, i.e., toward less negative values.Surprisingly, adsorption of PECs with a net negative zeta potential (atR=0.5 here) delivers significant numbers of anionic (negative) charges,due to the ionized carboxylate groups of the PAA of the PECs to thespore surface, more than compensating for the loss of anionic chargesdue to interactions between the spore surface and the cationic chargesof the DADMAC of the PECs. Thus, the zeta potential of the spores due tomodification by the PECs is shifted in an anionic (negative) direction.

The results in Table 10.2 also show that the zeta potential of the samenumber of spores may be adjusted by adsorption of PECs with a netnegative charge over a very wide range of PEC concentrations. Even atthe extremely low concentration of PECs (expressed as total polymerconcentration) of 0.0015 mM, the zeta potential of the spores may beadjusted to values significantly more negative than that of the nativespores at the same pH. Thus, the adsorption of PECs for the modificationof spores is a very effective and simple approach. Those skilled in theart will realize that the use of PECs for the modification of surfacesadvantageously overcomes the limitations of the use of ordinarysurfactants for surface modification.

For example, it is well known that the adsorption of surfactants ontosurfaces is drastically reduced when the surfactant concentration in theaqueous solution is decreased below the critical micelle concentrationof the given surfactant, due to the equilibrium distribution ofsurfactant molecules between micelles, monomeric surfactant, thesolid-liquid and the air-liquid interfaces. Since the PECs of theinstant invention do not exhibit a critical micelle concentration likesurfactants do, their adsorption onto solid surfaces of all types,including microorganisms, is extremely efficient. Also, unlikesurfactants, the PECs of the instant invention may not be efficient atlowering the surface tension of water, but can, like surfactants,improve the wetting and spreading of aqueous solutions on surfacesthrough their adsorption onto the surfaces, which can modify thesurfaces directly, increasing their affinity for water.

In addition, since the net negative PECs present in formulation PDS1were made via the dilution of PECs precursor solutions of the instantinvention, a very wide range of dilution factors, with the advantages ofusing “concentrates” to treat large volumes of solutions comprisingmicrobes (for example, bacterial spores) may be readily accomplished.

The results in Table 10.2 also show that the zeta potential of sporesmay be adjusted to positive values through exposure to PECs exhibiting anet positive charge. Exposure of the spores to aqueous solutionscomprising PECs made via dilution of precursor solutions formulated at avalue of the R parameter greater than 1.0 (here 4.0) results inadsorption of the PECs onto the spores, resulting in a shift of the zetapotential of the spores from −27.4 (control spores) to +31.6, eventhough the pH of the aqueous solution is neutral, about pH 7, which iswell above the isoelectric point of the spores. Inventors believe,without being bound by theory, that the significant increase in zetapotential of the spores is due to adsorption of PECs that leads toovercompensation of charges on the spore surface, and hence a largeincrease in the zeta potential. The data also show that the zetapotential of the spores may be adjusted to values even more positive(cationic) than that of the native spores well below their isoelectricpoint (point of zero charge). Thus, the zeta potential of the spores inwater at pH 2 is found to be +12.4, while in the presence of netcationic PECs (R=4) at pH 7, the zeta potential is +31.6, i.e.,“overcompensated”, as explained above.

The results in Table 10.2 also show that, for the same number of spores,a reduction in the concentration of the PECs (expressed as total polymerconcentration) to 0.0015 mM still results in the modification of thezeta potential of the spores in the positive (cationic) direction. At0.0015 mM total polymer concentration, the zeta potential of the sporeswas found (for two independent preparations of modified spores) to be+7.03 and +6.45, well above the native value of the spores in water atpH 7, which was −27.4. Thus, as described above, a very wide range ofdilution factors, with all of the advantages of the design of“concentrates” capable of delivering PECs mentioned above, are alsoavailable for the modification of spore surface charges in the positive(cationic) direction.

Example 11—Modification of the Zeta Potential of Bacillus Spores ViaInteractions with PECs Produced by the Dilution of PEC PrecursorSolutions in Multiple Steps

As described above, the zeta potential of spores may be adjusted to morenegative values by exposure to PECs of net anionic charge. In thisexample, sample DPAO3 was used to modify the surfaces of spores. SampleDPAO3 comprised PECs of anionic charge made via dilution of a precursorsolution with a surfactant solution comprising an amine oxide. The samenumber of spores were modified by exposure to the charge-reversed PECsin sample DPAOQ1, which comprised the PECs, an amine oxide and agermicidal quat. In addition, in a demonstration of an alternativeprocess, the spores which had been modified by the adsorption of theanionic PECs from formulation DPAO3 were further modified by theaddition of an aqueous solution (100 microliters of BTC1010 in water at0.2%) of the germicidal quat to 900 microliters of the spore dispersion,to yield the same total polymer and quat concentration (0.02%) as waspresent in the spore dispersion treated in one step.

TABLE 11.1 Characterization of Bacillus Subtilis Spore DispersionsContaining At least 1 × 10⁶ spores/ml in Absence and Presence of PECsPrepared from Precursor Solutions Total Polymer Zeta Formulation Rconcentration, Potential of Name value mM Spore, mV Comments Control 1 —— −27.4 Spores only dispersed in water, pH 7 Control 2 — — +12.4 Sporesonly dispersed in 0.01N HCl, pH 2 DPAO3 0.5 1.5 −44.8 Spores with PECsproduced from dilution of precursor solution DPAO3A 0.5 1.35 +34.6 Quatadded to subsample of Spores modified by DPAO3 DPAOQ1 0.5 1.35 +36.3Spores with charge-reversed decorated PECs

The results shown in Table 11.1 indicate that the zeta potential of thespores modified by exposure to the PECs in sample DPAO3 was negative, asexpected. Since sample DPAO3 comprises stable PECs and an amine oxidesurfactant, it also serves as an example of a ready to use hard surfacecleaner that comprises PECs that could be used to modify the surfaces ofspores. The results also indicate that the addition of quat to the samespore dispersion in a second step (sample DPAO3A) results in adsorptionof a significant amount of quat to the modified spore surface, resultingin a reversal of the spore zeta potential to positive (cationic). Theresults also indicate that the modification of the spore surfacesthrough adsorption of charge-reversed decorated PECs may be accomplishedin a single step, (sample DPAOQ1) resulting in reversal of the sporezeta potential to a very similar, positive value.

The results also indicate that the PECs of the instant invention may beused to modify the surfaces of microbes, such as bacterial spores asused here, including the anchoring of a germicidal quat. The anchoringof the germicidal quat may be accomplished with a single exposure of thespores to an appropriate solution of PECs, or may be accomplished in atwo-step process, wherein a PEC of net anionic charge is first adsorbedonto the spores, followed by exposure of the modified spores to anaqueous solution comprising the germicidal quat which causes adsorptionor anchoring of the quat onto the spore surface.

Example 12—Nontoxic Surface Modification of Bacillus subtilis Spores

In order to increase the adhesion of beneficial spores to seeds or cropsurfaces bearing native anionic (negative) charges, the zeta potentialof the spores may be adjusted to positive (cationic) values throughmodification by PECs formulated at R values >1.0 at pH values of about7.0. Such an embodiment may for example be advantageous in adheringbeneficial nitrogen fixing bacteria to seeds or roots of crops. In suchan application, the PECs should be nontoxic to the bacteria generated bygermination of the spores under favorable conditions. In this example,PECs produced via dilution of PEC precursor solutions PDS2 and PDS2Adescribed in Example 10 (R value of 4.0) were used to modify thesurfaces of Bacillus subtilis spores, providing spores with positive(cationic) zeta potentials, as discussed above.

Serial dilution of concentrated cell suspensions followed by plating ona solid growth medium is a common way to determine the viable cells, orcolony forming units (CFU), in the suspension. The CFU multiplied by therelevant dilution factor relates back to the viable microbes in theoriginal suspension. Those skilled in the art recognize that theautomated spreading of microbial suspension in a spiral formation fromthe center to the periphery of a circular plate containing solidmicrobial growth medium simultaneously accomplishes dilution and CFUdetermination of a microbial spore suspension through deposition over anever lengthening area of the solid medium. Standard recognition softwarecan visualize colonies on the solid medium and calculate the CFU/ml ofthe original suspension based on the distance and number of coloniesrelative to the center of the plate. Such an approach is implementedwith commercially available equipment, such as the Autoplater ModelAP5000 (Advanced Instruments). The inventors have utilized this methodto determine the viability of Bacillus subtilis spores modified by thePECs of the instant invention.

Spores were suspended at 1×10⁶ CFU/ml in formulation PDS2, PDS2A orsterile water. The spore suspension was then further diluted 1:100 insterile distilled deionized water and spiral plated. After overnightincubation at 37° C. to allow growth and visualization of colonies, theCFU values were determined. The results in Table 12.1 below show thatthe PEC solutions did not interfere with the ability of the spores toform colonies when placed on growth medium, i.e. no significantdifferences between the number of viable spores in the control ormodified spore dispersions are detected. Thus, although the cationicpolymer poly(DADMAC) is present in the PECs formed from dilution of thePEC precursor solutions, there is no toxicity to the spores observedwhich might be due to this polymer. Of course, where germicidalcharacteristics are desired, a quaternary ammonium compound or othergermicidal surfactant may be included.

TABLE 12.1 Viability of Modified Bacillus subtilus Spores Determined ViaSpiral Plating Formulation CFU/ml Observed Control - Spore suspensiononly 1.14 × 10⁴ Spore Suspension Exposed to PDS2 1.13 × 10⁴ SporeSuspension Exposed to PDS2A 9.04 × 10³

Example 13—Modification of Solid Surfaces by PEC Compositions PreparedVia Dilution of Precursor Solutions and their Measurement by QCM-D

TABLE 13.1 PEC Compositions with Surfactants Produced Via Dilution ofPrecursors for Characterization by QCM-d Total polymer Pre- concen-Succinic Surfac- Surfac- Surfac- Surfac- Surfac- Surfac- FormulationPrecursor cursor, Water, tration, R Acid, tant 1, tant 1, tant 2, tant2, tant 3, tant 3, Name sample grams grams mM value mM grams wt % gramswt % grams wt % Comments DADPAA 43 DADPAA 10 1.95 497.05 1.5 4.0 1.0 — —— — — — DPQ 3 DADPAA 10 1.95 497.05 1.5 4.0 1.0 5.0 0.40 — — — — Quatinto PECs DPEA 1 DADPAA 10 1.95 495.05 1.5 4.0 1.0 — — 2.0 0.40 — — SA7into PECs DPAO 4 DADPAA 10 1.95 490.60 1.5 4.0 1.0 — — — — 6.5 0.40 LOinto PECs Notes: Surfactant 1: Quaternary ammonium surfactant; BTC 1010,Stepan Corp.; 40 wt % aqueous solution. Surfactant 2: Ethoxylatedalcohol surfactant; Ecosurf SA-7, Dow Chemical Corp.; 100% actives.Surfactant 3: Amine oxide surfactant; Ammonyx LO, Stepan Corp.; 31 wt %aqueous solution.

TABLE 13.2 Characterization of PEC Compositions in Table 10.1 by QCM-DFormulation R Surfactant, Mass Adsorbed, Mass after Rinsing, Name valuewt % Surfactant type ng/cm² ng/cm² DADPAA 43 4.0 0.00 None 175 ± 6  188± 6  DPQ 3 4.0 0.40 Quaternary ammonium 276 ± 30 140 ± 50 DPEA 1 4.00.40 Ethoxylated alcohol 210 ± 25 175 ± 20 DPAO 4 4.0 0.40 Amine oxide196 ± 52 175 ± 55

Example 14: Crystal Growth Inhibition by PECs

A. Inhibition of Calcium Carbonate Crystal Growth by PECs in Laundry

Ashing or white residue on clothes during laundering may be caused byencrustation of the fibers by calcium carbonate precipitation. Calciumcarbonate is a ubiquitous insoluble salt found in municipal hard waterand is also a by-product of the laundering process. Ashing on fibers canbe reduced by inhibition of calcium carbonate crystal growth.Polyelectrolyte complexes can inhibit crystal growth by incorporation ofthe PEC moiety into the crystal lattice so as to prevent furtherdeposition of Ca²⁺ ions onto the seeded crystal. The inhibitionefficiency is a function of the R value of the PEC s.

The ability of the polyelectrolyte complex to inhibit crystal growth canbe measured by monitoring the change in turbidity of the solution uponthe addition of the PEC solution. The following experimental procedurewas followed:

300 ppm of 2:1 Calcium:Magnesium Chloride and 4.0 mM of Sodiumbicarbonate were added to 1000 mL of deionized water to form calciumcarbonate in-situ. 8.25% sodium hypochlorite solution with 130 mM totalpolymer as PEC precursor was added to this solution under constantstirring. This amounted to 0.22 mM total polymer in the diluted state.Turbidity of the solution was monitored with a Hach 2100 AN Turbidimeterinstrument over a period of 60 minutes. 3 Different R values werestudied: R=0.5 (anionic rich), R=1.33 (cationic rich) and R=4.0 (verycationic rich). Turbidity of hard water without PECs, and turbidity ofsodium hypochlorite solution in hard water, also without PECs, was alsomeasured for reference. The results are shown in Table 14.1 below, aswell as FIG. 1.

TABLE 14.1 Control Compositions and PEC Compositions for InhibitingTurbidity R = 0.5 R = 1.3 R = 4 Raw Material wt % active wt % active wt% active PolyDADMAC 0.697 1.195 1.674 PolyAcrylic Acid 0.616 0.396 0.185Sodium Hypochlorite 8.25 8.25 8.25 Sodium Hydroxide 0.347 0.104 0.104D.I. Water Balance balance balance

B. Inhibition of Crystal Growth of By-Products from Metal OxidationCaused by Hypochlorite

It has been demonstrated previously that the reaction of iron andmanganese ions with hypochlorite can cause significant yellowing andfabric damage to fabrics during the wash process. The rust-likebyproducts of this chemical reaction precipitate and readily attach tocertain fabrics, causing a dingying effect on the fabrics. The fabricswill appear yellowed, dulled and dingy as a result. Without being boundby theory, it is generally believed that hypochlorite readily andrapidly oxidizes metal ions to their rust-like byproducts, i.e. ironoxidizing to rust or iron oxide. The use of polymeric sequesteringagents acts as a dispersant, preventing the metal ions from depositingonto the fabric. Also, they may act as crystal growth inhibitors,helping to slow the aggregation of these rust-like byproducts.

The use of sequestering agents in preventing oxidized metal deposition.Similarly, the inventors observe that the PEC formulations described inthe present application produce a similar effect when in the presence ofMn(II) and Fe(II) ions. A sample experimental procedure is as follows:

An aqueous solution of 1760 ppm Fe(II) and 275 ppm Mn(II) ions wasmixed. The solution was separated into 250 ml aliquots. To each aliquot,2 ml of the described PEC formula and/or virgin sodium hypochlorite(diluted to 8.25% activity) was added respectively. The solutions weremixed immediately, causing the formation of dark brown oxidized metalprecipitate. A small unbrightened cotton swatch was added to eachaliquot and stirred for 1 minute, allowing the solution to saturate thecotton. The swatches were removed from the solution and squeezed dry.The difference in whiteness was easily observed, as the PEC-treatedfabric remained white, while the non-PEC treated fabric adsorbed a largeamount of the rust-like precipitate and appeared very brown and dulled.

Without departing from the spirit and scope of this invention, one ofordinary skill can make various changes and modifications to theinvention to adapt it to various usages and conditions. As such, thesechanges and modifications are properly, equitably, and intended to be,within the full range of equivalence of the following claims.

1. A concentrate composition comprising: (a) a water-soluble firstpolyelectrolyte bearing a net cationic charge or capable of developing anet cationic charge wherein said first polyelectrolyte is apoly(diallyldimethyl ammonium chloride) homopolymer; (b) about 0.001% to0.19% by weight of a water-soluble second polyelectrolyte bearing a netanionic charge or capable of developing a net anionic charge whereinsaid second polyelectrolyte comprises at least one of poly(acrylicacid), a copolymer of acrylic acid and maleic acid, a copolymer ofacrylic acid and styrene, a copolymer of styrene sulfonic acid andmaleic acid, a homopolymer of styrene sulfonic acid, or mixturesthereof; (c) about 0.1 to 10% by weight of a surfactant; (d) wherein thecomposition is free of precipitates, synthetic block copolymers,silicone copolymers, cross-linked poly(acrylic) and cross-linkedwater-soluble polyelectrolyte; (e) wherein the composition has aviscosity of less than about 1,000 centipoise; (f) wherein upondilution, the concentrate composition forms a polyelectrolyte complexfrom the first polyelectrolyte and the second polyelectrolyte; and (g)wherein R, the molar ratio of charged groups present on said firstpolyelectrolyte to oppositely charged groups present on said secondpolyelectrolyte, is from about 0.1 to
 20. 2. The composition of claim 1,wherein the composition further comprises a buffer.
 3. The compositionof claim 1, wherein the composition further comprises a dye.
 4. Thecomposition of claim 1, wherein the composition further comprises afragrance.
 5. The composition of claim 1, wherein the compositionfurther comprises a chelating agent.
 6. The composition of claim 1,wherein the composition further comprises a hydrotrope.
 7. Thecomposition of claim 1, wherein the composition further comprises athickener.
 8. The composition of claim 1, wherein the compositionfurther comprises an acid.
 9. The composition of claim 1, wherein thecomposition further comprises a base.
 10. The composition of claim 1,wherein the composition further comprises a solvent.
 11. A concentratecomposition comprising: (a) about 0.001 wt % to about 5.0 wt % of awater-soluble first polyelectrolyte bearing a net cationic charge orcapable of developing a net cationic charge wherein said firstpolyelectrolyte is a poly(diallyldimethyl ammonium chloride)homopolymer; (b) a water-soluble second polyelectrolyte bearing a netanionic charge or capable of developing a net anionic charge; (c) anoxidant comprising at least one of hydrogen peroxide, alkaline metalsalts and/or alkaline earth metal salts of hypochlorous acid,hypochlorous acid, solubilized chlorine, any source of free chlorine,solubilized chlorine dioxide, acidic sodium chlorite, active chlorinegenerating compounds, active oxygen generating compounds,chlorine-dioxide generating compounds, solubilized ozone, sodiumpotassium peroxysulfate, sodium perborate, or combinations thereof; (d)wherein the composition is free of precipitates, synthetic blockcopolymers, silicone copolymers, cross-linked poly(acrylic) andcross-linked water-soluble polyelectrolyte; (e) wherein upon dilution,the concentrate composition forms a polyelectrolyte complex from thefirst polyelectrolyte and the second polyelectrolyte; and (f) wherein R,the molar ratio of charged groups present on said first polyelectrolyteto oppositely charged groups present on said second polyelectrolyte, isfrom about 0.1 to
 20. 12. The composition of claim 11, wherein thecomposition further comprises a buffer.
 13. The composition of claim 11,wherein the composition further comprises a dye.
 14. The composition ofclaim 11, wherein the composition further comprises a fragrance.
 15. Thecomposition of claim 11, wherein the composition further comprises achelating agent.
 16. The composition of claim 11, wherein thecomposition further comprises a hydrotrope.
 17. The composition of claim11, wherein the composition further comprises a thickener.
 18. Thecomposition of claim 11, wherein the composition further comprises anacid.
 19. The composition of claim 11, wherein the composition furthercomprises a base.
 20. The composition of claim 11, wherein thecomposition further comprises a solvent.